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    • 专利摘要:
    Particle detection device comprising a support, a platform (4) for accommodating particles, four beams (12.1, 12.2, 12.3, 12.4) suspending the platform (4) from the support (2), so that the platform (4 ) can be vibrated, vibration means (8) of said platform (4) at a resonant frequency, detection means (10) of displacement of the platform (4) in a direction of displacement. Each beam (12.1, 12.2, 12.3, 12.4) has a length I, a width L and a thickness e and the platform (4) has a dimension in the direction of travel of the platform and in which in an out-of-plane mode device I ≥ 10 xL and the dimension of each beam in the direction of travel of the platform (4) is at least 10 times smaller than the dimension of the platform (4) in the direction of travel.
    公开号:FR3076290A1
    申请号:FR1850025
    申请日:2018-01-03
    公开日:2019-07-05
    发明作者:Sebastien Hentz；Marc SANSA PERNA
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    DEVICE FOR MICRO OR NANOMECHANICAL DETECTION OF PARTICLES
    DESCRIPTION
    TECHNICAL AREA AND PRIOR ART
    The present invention stands relates to a device of detection mechanical putting implemented structures micromechanics and / or nanomechanics resonant.The device detection can be used in the detection
    gravimetric and more particularly in chemical sensors for gas detection, in biological sensors and in mass spectrometers based on resonant micromechanical and / or nanomechanical structures.
    A mass spectrometer is a mass detector used to determine the mass of individual particles. It is for example used in biology to determine the mass of biological cells. A resonant micro and / or nanomechanical system can be used in a mass spectrometer. The system comprises a beam or a structure capable of accommodating for example a biological cell, the beam or the structure is excited at its resonant frequency. The deposition of a biological cell modifies the mass of the beam or structure and therefore modifies its resonant frequency. By measuring and processing the variation in resonance frequency, corresponding to the deposition of each biological cell, we can deduce the mass of the biological cell.
    The document A. Rahafrooz and S. Pourkamali, Fabrication and characterization of thermally actuated micromechanical resonators for airborne particle mass sensing: I. Resonator design and modeling, J. Micromechanics Microengineering, vol. 20, no. 12, p. 125018, 2010 describes a micromechanical resonator for detecting the mass of particles in the air. This resonator has a platform suspended from its four vertices by four beams. Two of these beams are active, that is, they are dedicated to activating and detecting the movement of the platform. Each active beam is divided in two and is connected to two different electrodes, so that a current can flow through the beam. The actuation is obtained by circulating a modulated current in the beam and the detection is obtained by detecting the current flowing through the beam due to the piezoresistive effect. Following the activation, the mass is vibrated in the plane. On the one hand, this device comprises beams of complex shape. In addition, they require two electrical connections each, which limits its minimum achievable dimensions for the device. The manufacture of this device is complex. On the other hand, the fact of circulating current through the beam causes a heating of the structure and modifies its properties. In addition, this heating limits the choice of materials suitable for making the beams. In addition, this structure is not suitable for excitation and / or detection of out-of-plane modes.
    STATEMENT OF THE INVENTION
    It is therefore an object of the present invention to offer a particle detection device having a simplified structure compared to that of the particle detection devices of the prior art.
    The aim stated above is achieved by a particle detection device comprising a platform, at least one face of which is intended to receive the particle or particles to be detected, means for suspending the platform so that it can be put in vibration, means for vibrating said platform, the suspension means comprising at least two beams, said beams being configured to deform when the platform is vibrated, the beams and the platform being dimensioned so that, when the vibration of the platform, it is not or little deformed by the action of the deformed beams. The detection device also includes means for detecting the movement of the platform.
    Preferably, the beams have a length between the support and the platform at least ten times greater than the dimensions of the section of the beams. The dimension of the beams in the direction of the vibration movement is at least ten times smaller than the dimension of the platform in this direction.
    In examples of displacements in the plane and off-plan of the platform, the beams are deformed in bending.
    In an exemplary embodiment, the detection means implement the beams of the suspension means which are for example made of piezoresistive material.
    In another exemplary embodiment, the detection means are optical and include an optical resonator disposed near the platform, so that the movement of the platform modifies the optical properties of the resonator.
    The subject of the present invention is therefore a device for detecting particles comprising a support and at least one structure movable relative to the support, said movable structure comprising a platform, at least one face of which is intended to receive the particle or particles to be detected, means for suspending the platform so that the platform can be vibrated relative to the support, means for vibrating said platform at at least one of its resonant frequencies, means for detecting the movement of the platform in a given direction, the suspension means comprising at least two beams configured to deform when the platform is vibrated. Each beam has a length I, a width L and a thickness e and the platform has a dimension in the direction of movement of the platform. The dimension of each beam in the given direction of movement of the platform is at least 10 times smaller than the dimension of the platform in the given direction of movement, and in the case of a mode I detection device > 10 xL and in the case of a detection device in out-of-plane mode I> 10 xe, so that, when the platform is vibrated, it is not or only slightly deformed by the action beams.
    In an exemplary embodiment, the suspension means comprise at least a first beam and a second beam, the first and second beams being arranged symmetrically with respect to the direction of movement.
    In one example, the actuation means can be external to the mobile structure.
    In another example, the actuation means can act directly on the platform. The actuating means can be optical means applying a gradient force at the resonance frequency to the platform or electrostatic means applying an electrostatic force at the resonance frequency on the platform.
    In an exemplary embodiment, at least two beams are made of piezoresistive material, for example silicon, and the detection means comprise a constant voltage source intended to apply a potential difference to said beams, means for measuring a current in exit of said beams.
    The detection means may include an optical resonator arranged near the platform so that the displacement of the platform modifies an evanescent field of the optical resonator, a waveguide intended to inject a light beam into the optical resonator and to collect said light beam leaving the optical resonator.
    In an advantageous example, the detection device comprises several mobile structures arranged around the optical resonator, the movement of each platform modifying the evanescent field of the optical resonator.
    In an exemplary embodiment, the platform is rectangular and the two beams are fixed to a first side of greater length of the platform and perpendicular to said first side, two other beams are fixed to a second side of greater length of the platform perpendicularly second side audit. The beams can be straight and parallel to each other.
    The beams can be fixed to the first and second longer sides at a distance from the longitudinal ends of the first and second longer sides.
    In an exemplary embodiment, the beams are made of a material different from that of the platform.
    The present invention also relates to a mass spectrometer comprising, means for ionizing an analyte, means for focusing the ionized analyte and at least one detection device according to the invention disposed downstream of the focusing means .
    BRIEF DESCRIPTION OF THE DRAWINGS
    The present invention will be better understood on the basis of the description which follows and of the appended drawings in which:
    FIG. 1 is a top view of an exemplary embodiment of a detection device with mode of movement in the plane,
    FIG. 2A is a perspective view of the detection device in FIG. 1,
    FIG. 2B is a detailed view of FIG. 2A,
    FIG. 3 is a schematic representation of the device of the figure in the excitation phase,
    FIG. 4 is a top view of a detection device comprising piezoresistive detection means,
    FIG. 5A is a top view of an example of a detection device with displacement in the plane comprising optical detection means,
    FIG. 5B is a top view of an example of an out-of-plane mode device comprising optical means which can be used for actuation or for detection,
    FIG. 6 is a top view of another exemplary embodiment of the device in FIG. 1,
    FIG. 7 is a top view of another embodiment of the device in FIG. 1,
    FIGS. 8A to 8D are top views of alternative embodiments of the device according to the invention,
    FIG. 9 is a side view of a detection device according to another embodiment with out-of-plane displacement mode,
    FIG. 10 is a top view of a detection device according to yet another embodiment,
    FIG. 11 is a schematic representation of a mass spectrometer implementing a detection device according to the invention,
    FIGS. 12A to 12C are schematic representations of a top and side view of elements obtained during different stages of an exemplary method of producing a detection device in FIG. 1.
    FIG. 13 is a top view represented diagrammatically of an example of a device according to the invention with thermal actuation,
    FIG. 14 is a view identical to that of FIG. 1 with particles deposited on the platform,
    FIGS. 15A and 15B are schematic representations of a top and side view of elements obtained during different stages of an example of a method for producing a variant of the detection device of FIG. 1,
    FIGS. 16A and 16B are schematic representations of a top and side view of elements obtained during different stages of an exemplary method of producing a detection device in FIG. 9.
    DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS
    The resonant detection device according to the invention is intended to detect the presence of particles deposited on a reception platform. The particles have for example dimensions of a few nm. The particles can be biological particles (molecules, proteins, viruses, etc.), particles contained in the air or gas.
    In all the figures, the arrows represent the direction of movement of the platform under the action of the actuating means.
    As we will see below, the term "beam" designates both rectilinear elements of constant cross section, non-rectilinear elements, and elements of variable section continuously and / or per portion.
    In FIGS. 1 and 2A, one can see an embodiment of a detection device D1 in mode in the plane according to the invention.
    It comprises a support 2, a reception platform 4 for the particles, designated “platform”, suspension means 6 from the platform 4 to the support 2, so that the platform 4 is able to move relative to the support 2. In this example, it is considered that the platform 4 is intended to move in the XY plane of the device as is shown diagrammatically in FIG. 3. Z is orthogonal to the XY plane and will be designated "out-of-plane direction".
    The platform extends in a plane which is parallel to the XY plane of the detection device.
    In the example shown in Figure 1, the platform has openings which are used in certain manufacturing processes. These openings can be omitted.
    The detection device also includes actuation means 8 capable of vibrating the platform in the XY plane at at least one resonant frequency.
    The device also includes means 10 for detecting the movement of the platform 4, more particularly variations in the movement of the platform due to the deposition of a particle on the platform.
    The suspension means comprise at least two beams. In the example shown, the suspension means 6 comprise four beams 12.1, 12.2, 12.3, 12.4.
    Each beam 12 is anchored by one end to the support 2 and by another end to the platform 4.
    In the example shown, the platform has a rectangular shape, two beams 12.1, 12.2 being anchored to the platform 4 along a first side 4.1 of the platform, and the other two beams 12.3, 12.4 are anchored to the platform on along a second side 4.2 parallel to the first side.
    In the example shown, the beams 12.1, 12.2 are anchored to the platform at a distance from the longitudinal ends of the first side 4.1 and the beams
    12.3, 12.4 are anchored to the platform at a distance from the longitudinal ends of the second side 4.2. Alternatively, the beams are anchored to the platform at the longitudinal ends of the second sides.
    In this example, the beams 12.1 and 12.2 are parallel to each other and the beams 12.3 and 12.4 are parallel to each other, the beams 12.1 and 12.3 are aligned and the beams 12.2 and 12.4 are aligned and are parallel to the X axis.
    In this example, the beams have a constant cross section in a YZ plane.
    The beams have a length I in the direction X, a width L in the direction Y and a thickness e in the direction Z (figure 2B).
    The dimensions of the platform are designated a in the X direction and b in the Y direction.
    As shown schematically in Figure 3, the platform 4 is intended to move along the direction Y. The 12.1 to 12.4 are then deformed in bending.
    The mobile structure comprising the platform and the beams, is dimensioned so that during the movement of the platform and the deformation of the beams, the platform is not or only slightly deformed under the action of the beams.
    For this we choose:
    (la) - For an operation in the plane, the length I of the beams equal to at least 10 times the width L of the beam:
    l> 10xL (II) - the dimension of the beams in the direction of movement of the platform is at least 10 times smaller than the dimension of the platform in the direction of movement.
    In the example of FIGS. 1 to 3, the direction of movement is the direction Y in the plane, then L <10xb.
    The platform can have dimensions, for example, of 100 nm x 100 nm surface up to 100 pm x 100 pm, regardless of the mode of operation. The thickness of the platform can be, for example, from 10 nm to 100 μm.
    The beams can for example have a section of between 25 nm x 25 nm and 10 pm x 10 pm; and a length between 250 nm and 100 pm.
    An example of non-limiting dimensions is given below. The device comprises a rectangular platform suspended by four beams for a mode in the plane. The platform and the beams have a thickness in the Z direction of
    220 nm. The platform has external dimensions of 3 pm x 1.5 pm. The beams have a length in the X direction of 1.5 µm and a section of 100 nm x 220 nm.
    In another embodiment of a device suitable for operation in out-of-plane mode, the platform has a surface of 3 μm x 1.5 μm and a thickness of 300 nm The supports have a length of 1 μm, a dimension L of 100 nm and a thickness e of 30 nm.
    Thus the beams have a substantially lower stiffness than the stiffness of the platform in the direction of movement, which reduces the risk of deformation of the platform in the direction of movement.
    The mass Mm of the particle capable of being measured is much less than the mass of the platform Mp, advantageously Mm <Mp / 10.
    The minimum mass measurable by the detection device depends, for its part, on the performance of the detection device.
    In an exemplary embodiment, the actuation means are external to the mobile structure and comprise a piezoelectric vibrating element, also called a piezoshaker, to which the support 2 is fixed. When the piezoshaker is activated, the mobile structure is set in motion relative to to support. For example, if the mechanical actuation is at a resonant frequency, a mechanical amplification appears and the platform moves relative to the support.
    In FIG. 13, we can see another embodiment of a device adapted to the mode in the plane, in which the actuation means are of the thermal type. For this a current flows through the structure. The current mainly heats the beams by Joule effect, which are the most resistive elements because of their small section. The heating causes expansion of the supports, which causes an actuating force in the plane. Detection is piezoelectric. The beams 12.1 'to 12.4' are oriented relative to the edges of the platform 4 so as to form a non-right angle with them.
    We consider an actuation voltage at frequency f 0/2 .
    The piezoresistive beams of resistance R see their resistance varied according to R = R o + Ricps f 0 .
    The displacement of the platform due to thermal actuation is written x = x 0 cosf 0 .
    The detection current at the output is:
    / = / iCOs / o / 2 + I 1 cos (f 0 ~ fo / 2) + ZiCOs (/ o + / o / 2) / iCos (/ o- / o / 2) + / iCos (/ o + / o / 2) is the current resulting from the movement of the structure.
    In another exemplary embodiment, the actuation means are of the electrostatic type. For example, it has an electrode on the support opposite one face of the platform and oriented so that an electrostatic force generated between the electrode and the platform, moves the platform in the Y direction. In the example of Figure 1, the electrode is arranged opposite a side 4.2. By applying a potential difference with a constant component and a second component to the resonant frequency between the electrode and the platform, an electrostatic force proportional to the square of the potential difference, appears between the electrode and the platform, which is then vibrated at the resonant frequency. As a variant, it is possible to envisage implementing two electrodes, each facing one side of the platform, the potential differences applied to the electrodes are then phase shifted by half a period.
    According to another exemplary embodiment, the actuation means are of the optical type. They comprise, for example, an optical resonator, for example in the form of a ring, disposed near the platform. When the optical resonator is at resonance, a gradient force appears attracting the platform towards the ring. The gradient force is modulated at the resonant frequency, causing the platform to vibrate. The optical ring or rings are placed opposite one side 4.2 in the example of FIGS. 1 to 3.
    In FIGS. 4 and 5, one can see examples of detection means that can be implemented in the detection device.
    In FIG. 4, the detection means are of the piezoresistive type. The detection means use all or part of the beams 12.1 to 12.4 formed from a piezoresistive material. The beams are for example made of silicon.
    In the example shown, the four beams are made of piezoresistive material and participate in the vibration of the platform. In another example, only the beams 12.1 and 12.3 or 12.2 and 12.4 are made of piezoresistive material.
    The detection means also include a source 14 of constant voltage V and means 16 for measuring the output current I.
    In a homodyne mode, the constant voltage source is for example connected to the support to which the beams 12.1, 12.2 are anchored, and the means 16 for measuring the output current are connected to the support to which the beams 12.3, 12.4 are anchored.
    For example, assuming a displacement of the platform along the direction Y: y = y 0 cosf 0 , fo being the resonance frequency, then the resistance R of piezoresistive beams varies according to the following relation:
    R = R o + Ricos2f 0 .
    As a result, the output current can be written I = I 0 licos2f 0 .
    If a thermal actuation is combined with a piezoresistive detection, the resistance of the supports varies according to the relationship R = R o + Ricosf 0 , because the beams form an angle with the edges of the platform. In this case, the current flowing through the structure is at frequency f 0/2 due to thermal actuation, so that the output current has terms at three different frequencies: that of the actuation frequency, and two additional components which only appear when the structure is in resonance. These components can be measured using heterodyne detection methods or a spectrum analyzer.
    If a particle is deposited on the platform, the resonance frequency is modified, causing a variation of R and a variation of I. By treating this variation, we can go back to the mass of the deposited particle.
    As a variant, a heterodyne detection can be carried out, by implementing a voltage source modulated at a certain frequency, the frequency of the output current being known and fixed.
    The use of piezoelectric detection means has the advantage of being reduced in size, which makes it possible to optimize the capture surface on the same chip.
    In FIG. 5A, we can see another exemplary embodiment of detection means, in which the detection means are of the optical type, adapted to a device having a mode in the plane.
    In the example shown, the detection means comprise an optical device comprising at least one waveguide 18 and an optical resonator 20 in the form of a ring, which is coupled to the one guide 18 by an evanescent coupling. The optical device also includes a light source, for example a laser (not shown) optically coupled to the waveguide 18.
    The optical ring 20 is fixed to the support 2 and located near the platform, so that at least one edge of the platform is in the evanescent field of the ring and that the movement of the ring influences the evanescent field. . For example, the distance between the ring and an edge of the platform is of the order of 100 nm.
    The orientation of the ring relative to the platform is such that when the platform is vibrated, the distance between the ring and the platform varies, while remaining within the perimeter of the evanescent field.
    A light wave of constant power is injected into the optical ring. The movement of the platform near the ring modifies the optical properties of the ring, whose optical resonance frequency, the light power recovered by the waveguide 18 is then modulated due to the influence of the movement of the platform on the optical properties of the ring. By using spectrometric means, it is possible to obtain an output power of the light beam proportional to the movement of the platform.
    For a platform having a displacement along the direction Y y = y 0 cosf 0 , considering at the input of the waveguide, a light power at a constant wavelength λ 0 Ρ, η, χο, the power of output P or t, Ào is modulated into Pi + P 2 cosf 0 .
    As a variant, the optical detection means comprise an external laser and interferometric detection means.
    As a variant, it is possible to envisage having several platforms around the same optical ring, each platform being optically coupled to the ring. By using platforms of frequencies of different resonances, it is possible after treatment to separate the influences of the different platforms on the optical properties of the ring and thus to go back to the mass of each particle deposited on each platform. This device makes it possible to detect several particles simultaneously, the device then offers faster detection.
    An example of operation of the detection device according to the invention will now be described.
    The actuating means 10, for example optical or electrostatic, are activated so as to vibrate, at one of its resonant frequencies, the platform 4 along the direction Y, the beams 12.2 to 12.4 are deformed in bending as this is shown in Figure 3. Because of the dimensions of the beams and the platform, the deformations of the beams have little or no mechanical effect on the platform, the latter is little or is not deformed.
    The detection means, for example optical or piezoelectric, detect the vibratory movement of the platform.
    When a particle is deposited on the platform, the particle and platform assembly has a different resonance frequency than that of the platform alone. The detection means detect the modified vibrational displacement of the platform carrying the particle.
    The variation in resonant frequency is then treated and makes it possible to go back to the mass of the deposited particle.
    The detection device is integrated into a detection system comprising means for processing the measurement signals supplied by the detection device, in order to provide the mass of the deposited particle, or even the designation of the deposited particle.
    Thanks to the invention, whatever the place of the platform where the particle is deposited, the influence on the resonance frequency is the same or almost the same. Thus a single resonance mode is sufficient to detect a particle regardless of its location on the platform.
    In FIG. 14, one can see a device according to FIG. 1. Particles A1, A2, A3 have been shown diagrammatically at different locations on the platform.
    A finite element simulation gives the following results:
    For particles of mass m x :
    the deposition of the particle Al causes a frequency shift - = 1082.1 ppm; fo the deposition of the particle A2 causes a frequency shift
    Δ / 2 —— = 1082.5 ppm;
    Jo the deposition of particle A3 causes a frequency shift - = 1082.0 ppm;
    fo
    It can therefore be seen that, thanks to the invention, the frequency offset due to the deposition of a particle on the platform varies little as a function of the location of the deposition.
    For a mass m 2 = mi / 2 kg, the simulation gives for the particle Al ~~ = 541 ppm. By halving the mass, the frequency offset is roughly halved.
    The surface of the platform can be very large and can be adjusted according to the applications.
    The resonant frequency of the platform is easily adjusted by choosing the dimensioning of the beams of the suspension means, regardless of the shape of the platform.
    In the example shown in Figures 1 to 3, the beams are parallel to each other. According to another example of a device D2 represented in FIG. 6, the suspension beams of the platform 104 can be oriented so that their longitudinal axes are intersecting. In the example shown, the beams 112.1 and 112.2 and the beams 112.3 and 112.4 are arranged symmetrically with respect to the Y axis.
    In addition, the beams 212.1, 212.2 can have a shape other than a rectilinear shape, for example they can have the shape of a spring, as can be seen in the device D3 shown in FIG. 7. In this case the length at take into account in the inequalities I> 10 xL and I> 10 xe is the length of the developed spring.
    In addition, the beams can have a cross section of variable surface continuously or in portions. In this case, the inequalities (I) consider the maximum values of L and e, and the inequalities (II) consider the minimum value of e.
    In addition, the beams might not all have the same length, as shown in FIG. 8A, on which the beams 312.1 and 312.3 of the device D4 are shorter than the beams 312.2 and 312.4.
    In FIG. 8B, a variant of the device DI can be seen in which the platform 404 has recesses 414 in the direction X, for each of the beams and at the bottom of which one end of the beams 412.1 to 412.4 is anchored.
    In FIG. 8C, we can see another variant of the device DI comprising a platform 4 ′ in the form of a disc.
    In FIG. 8D, a variant of the optical actuation or detection device can be seen. In this example, an edge of the platform 4 '' has a recess 4.5 of shape corresponding to the optical disc to accommodate the latter. The optical disc 20 is partially bordered by an arc-shaped edge of the platform.
    It will also be understood that the number of beams is not limited to four, it can be envisaged to provide six or more beams. Preferably, the beams are distributed symmetrically with respect to the direction of movement to obtain a uniform movement of the platform.
    In another embodiment of a detection device D6, the platform is excited so that it has an out-of-plane movement, i.e. along the Z axis, as shown in FIG. 9.
    The mobile structure comprising the platform and the beams, is dimensioned so that during the movement of the platform and the deformation of the beams, the platform is not or only slightly deformed under the action of the beams.
    For this, we choose, for the beams 512.1 and 512.2 connecting the platform 504 to the supports 502:
    Ib - For an out-of-plane operation for which an example of a device will be described below, the length I of the beams equal to at least 10 the thickness e of the beam:
    I> 10 x e
    Condition II is written L <10xE, with E the thickness of the platform in the direction Z.
    According to the invention, the platform moves along the Z axis without deforming in bending.
    The actuation means able to set the platform 404 in motion along the direction Z can be the same as those used to generate a displacement in the plane. In the case of a piezoelectric shaker, this is such that it moves the support in the Z direction.
    In FIG. 5B, one can see an example of an out-of-plane mode device comprising optical means which can be used for actuation or for detection.
    The detection means comprise an optical ring disposed under the platform and a waveguide 18 in the plane of the ring. In the case of an implementation for detection, the displacement of the platform in the direction Z, near the ring modifies the optical properties of the ring, including its optical resonance frequency. The light power recovered by the waveguide 18 is then modulated due to the influence of the displacement of the platform on the optical properties of the ring. In this example, the platform advantageously protects the optical ring from mass deposition, which avoids added effects of mass on the optical response.
    The detection means capable of detecting the movement of the platform can be similar to those used for the detection of movements in the plane.
    According to another exemplary embodiment, the platform 604 can be excited in transverse modes in the plane relative to the support 602, ie modes in which the direction of movement corresponds to the longitudinal direction of the beams 612.1 to 612.4, ie in the direction in the representation of Figure 10. The beams are preferably in the form of a spring.
    In Figure 11, we can see a schematic representation of a mass spectrometer implementing the detection device according to the invention.
    The mass spectrometer comprises a vacuum chamber 700 supplied with a source of analyte 702, ionization means 704 of the analyte at the inlet of the chamber 700, focusing means 706 of the ionized analyte downstream of the means ionization and a mass sensor 708 according to the invention downstream of the focusing means. The sensor is connected to means for measuring and processing the signal 710 emitted by the sensor 708.
    An example of a method of manufacturing a detection device in FIGS. 1 to 3 will now be described in relation to FIGS. 12A to 12C.
    Preferably, the detection device can be produced by microelectronics techniques.
    For example, using a SOI 700 substrate (Silicon On Insulator in English terminology) or silicon on insulator comprising a silicon substrate 702, a layer of SiO 2 704 and a layer of silicon 706. This substrate is shown seen from the side. and seen from above in Figure 12A.
    During a following step, the layer 706 is structured, for example by photolithography and etching, so as to form the mobile structure in the layer 706 having the appropriate dimensions of the beams and of the platform to ensure low deformation, or even an absence of deformation of the platform when it is vibrated.
    The element thus obtained is shown in side view and in top view in Figure 12B.
    In a next step, the mobile structure is released, for example by anisotropic wet etching of SiO 2 704.
    The element thus obtained is shown in side view and in top view in FIG. 12C.
    It will be understood that the mobile structure can be made of another material, such as gallium, silicon nitride or aluminum.
    Furthermore, in the example described, the platform and the beams are made of the same material. In another example, they are made of different materials, for example having different mechanical properties. For example, the platform can be made of a material having a greater stiffness and the beams having a lower stiffness, for example by choosing a material with a higher Young's modulus for the platform than for the beams. For example, we can choose in the case of a device with displacement in the plane Spout x L "Platform x b, and in the case of a device with out-of-plane displacement Spout x e" Platform x E
    With Epoutre the Young's modulus of the material of the beam, Eplateforme the Young's modulus of the material of the platform and E the thickness of the platform.
    In addition, it is possible to envisage making the stack of FIG. 12A, and not starting from a stack already made.
    The minimum size of the detection device depends on the manufacturing process and on its ability to produce beams of small section. For example, if the manufacturing technology limits the minimum dimension of an element to 50 nm, the smallest section of the beams can be 50 nm x50 nm, it follows that the length of the beams is at least 500nm, and the platform has at least a minimum dimension of 500nm in the direction of movement.
    In FIGS. 15A and 15B, one can see represented diagrammatically the steps making it possible to produce a mode device in the plane, in which the platform is thinned and the beams are thick.
    First of all, the steps of FIGS. 12A and 12B are carried out, then a photolithography and an etching of the platform are carried out so as to make it thinner.
    The element thus obtained is represented in FIG. 15A.
    In a following step, the mobile structure is released, for example 5 by anisotropic wet etching of SiO 2 704.
    The element thus obtained is shown in side view in FIG. 15B.
    In FIGS. 16A and 16B, one can see represented diagrammatically the steps making it possible to produce a device in out-of-plane mode (FIG. 9), in which the beams are thinned relative to the platform.
    First of all, the steps of FIGS. 12A and 12B are carried out, then a photolithography and an engraving of the beams are carried out so as to make them thinner.
    The element thus obtained is represented in FIG. 16A.
    In a next step, the mobile structure is released, for example by anisotropic wet etching of SiO 2 704.
    The element thus obtained is shown in side view in FIG. 16B.
    权利要求:
    Claims (12)
    [1" id="c-fr-0001]
    1. Particle detection device comprising a support and at least one structure movable relative to the support (2), said mobile structure comprising a platform (4), at least one face of which is intended to receive the particle or particles to be detected, means for suspending (6) the platform (4) so that the platform (4) can be made to vibrate relative to the support (2), means for vibrating (8) from said platform (4) to at least one of its resonant frequencies, means for detecting (10) the movement of the platform (4) in a given direction, the suspension means (6) comprising at least two beams (12.1, 12.2, 12.3, 12.4) , configured to deform when the platform (4) is vibrated, in which each beam (12.1,12.2, 12.3,12.4) has a length I, a width L and a thickness e and the platform (4) has a dimension in the direction of movement of the platform, and in which
    the dimension of each beam in the given direction of movement of the platform (4) is at least 10 times smaller than the dimension of the platform (4) in the given direction of movement, and
    - in the case of a mode detection device in the plane I> 10 xL and in the case of an out-plane mode detection device I> 10 xe, so that, when the vibration of the platform (44), this is not or little deformed by the action of the beams.
    [2" id="c-fr-0002]
    2. Detection device according to claim 1, wherein the suspension means (6) comprise at least a first beam and a second beam, the first and second beams being arranged symmetrically with respect to the direction of movement.
    [3" id="c-fr-0003]
    3. Detection device according to claim 1 or 2, wherein the actuating means (8) are external to the mobile structure.
    [4" id="c-fr-0004]
    4. Detection device according to claim 1 or 2, wherein the actuating means (8) act directly on the platform.
    [5" id="c-fr-0005]
    5. Detection device according to claim 4, in which the actuation means (8) are optical means applying a gradient force at the resonance frequency to the platform or electrostatic means applying an electrostatic force at the resonance frequency on the platform.
    [6" id="c-fr-0006]
    6. Detection device according to one of claims 1 to 5, in which at least two beams are made of piezoresistive material, for example silicon, and in which the detection means comprise a constant voltage source (14) intended to apply a potential difference in said beams, means for measuring (16) a current at the output of said beams.
    [7" id="c-fr-0007]
    7. Detection device according to one of claims 1 to 6, wherein the detection means comprise an optical resonator (20) disposed near the platform (4) so that the movement of the platform (4) modifies a evanescent field of the optical resonator (20), a waveguide (18) intended to inject a light beam into the optical resonator (20) and to collect said light beam leaving the optical resonator (20).
    [8" id="c-fr-0008]
    8. Detection device according to one of claims 1 to 5 and 7, comprising several mobile structures arranged around the optical resonator, the movement of each platform modifying the evanescent field of the optical resonator.
    [9" id="c-fr-0009]
    9. Detection device according to one of claims 1 to 8, in which the platform (4) is rectangular, in which two beams (12.1, 12.2) are fixed to a first side of greater length (4.1) of the platform (4) and perpendicular to said first side (4.1), two other beams (12.3,12.4) are fixed to a second side of greater length (4.1) of the platform (4) perpendicular to said second side (4.1), and in which the beams (12.1, 12.2, 12.3,12.4) are straight and parallel to each other.
    [10" id="c-fr-0010]
    10. Detection device according to claim 9, in which the beams (12.1, 12.2, 12.3, 12.4) are fixed to the first and second sides (4.1) of greater length at a distance from the longitudinal ends of the first and second sides of greater length (4.1).
    [11" id="c-fr-0011]
    11. Detection device according to one of claims 1 to 10, in which the beams are made of a material different from that of the platform.
    [12" id="c-fr-0012]
    12 Mass spectrometer comprising, means for ionizing an analyte, means for focusing the ionized analyte and at least one detection device according to one of claims 1 to 11 disposed downstream of the focusing means.
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    同族专利:
    公开号 | 公开日
    CN109994364A|2019-07-09|
    EP3509214B1|2020-11-18|
    EP3509214A1|2019-07-10|
    US20190204205A1|2019-07-04|
    FR3076290B1|2020-02-07|
    US10794813B2|2020-10-06|
    引用文献:
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    EP3147673A1|2015-09-24|2017-03-29|Commissariat à l'énergie atomique et aux énergies alternatives|Optomechanical physical sensor with improved sensitivity|
    US5208458A|1991-11-05|1993-05-04|Georgia Tech Research Corporation|Interface device to couple gel electrophoresis with mass spectrometry using sample disruption|
    JP4840058B2|2006-09-29|2011-12-21|ブラザー工業株式会社|Optical scanning device, image display device including the same, retinal scanning image display device, and method of driving optical scanning element|
    US8390912B2|2007-01-10|2013-03-05|Seiko Epson Corporation|Actuator, optical scanner and image forming device|
    JP5589459B2|2010-03-15|2014-09-17|セイコーエプソン株式会社|Optical filter, optical filter module, analytical instrument and optical instrument|
    WO2014154283A1|2013-03-28|2014-10-02|Frauhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.V.|Optical sensor arrangement and method for measuring an observable|TWI647435B|2018-01-19|2019-01-11|國立清華大學|Thermally actuated oscillating suspended particle sensing device and suspended particle sensing method|
    CN110361116B|2019-08-14|2020-11-20|合肥工业大学|Four pressure membrane structure differential type quartz beam resonance pressure sensor|
    法律状态:
    2019-01-30| PLFP| Fee payment|Year of fee payment: 2 |
    2019-07-05| PLSC| Publication of the preliminary search report|Effective date: 20190705 |
    2020-01-30| PLFP| Fee payment|Year of fee payment: 3 |
    2021-01-28| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1850025A|FR3076290B1|2018-01-03|2018-01-03|DEVICE FOR MICRO OR NANOMECHANICAL DETECTION OF PARTICLES|
    FR1850025|2018-01-03|FR1850025A| FR3076290B1|2018-01-03|2018-01-03|DEVICE FOR MICRO OR NANOMECHANICAL DETECTION OF PARTICLES|
    EP19150014.9A| EP3509214B1|2018-01-03|2019-01-02|Micro or nanomechanical device for detecting particles|
    CN201910003107.4A| CN109994364A|2018-01-03|2019-01-02|Micromechanics or nano-machine particle detection device|
    US16/237,817| US10794813B2|2018-01-03|2019-01-02|Micro or nanomechanical particle detection device|
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