Micromechanical beam

Abstract

The present invention provides a micromechanical beam for scanning probe measurement, lithography, etc., which extends longitudinally between a fixed end and a free end. The beam has a height along a height direction perpendicular to the longitudinal direction, and the height is smaller than the width along the width direction. Furthermore, the beam has a bent portion provided at the fixed end in the longitudinal direction of the beam, and a reinforcing portion provided between the bent portion in the longitudinal direction and the free end. The beam has a base element and a reinforcing structure provided on the base element within the reinforcing portion, and the reinforcing structure is configured to increase the bending stiffness of the beam within the reinforcing portion with respect to bending in the height direction.

Description

[Technical Field]

[0001] The present invention relates to a micromechanical beam for scanning probe measurement, lithography, and the like, and to a method for producing such a beam. [Background technology]

[0002] Micromechanical beams are used to measure forces at the atomic level and to characterize the surfaces of various materials, particularly in atomic force microscopes (AFMs). In other applications, micromechanical beams are used as lithography tools to pattern surfaces. Due to their resolution and versatility, AFMs have become important measuring and lithography instruments in a wide range of fields, from semiconductor manufacturing to biological research.

[0003] Active beam-based AFM can achieve atomic-level resolution. Recent research on high-resolution AFM has been conducted on various types of surfaces in air, liquid, or vacuum by employing piezoelectric scanning devices and active beams fabricated as microelectromechanical systems (MEMS). MEMS-based force detection (probe-based instruments) provide high-quality imaging at high imaging rates by using a sharp tip at one end of the beam and characterizing the sample surface with low load or low trackability. In lithography mode, the tip is modified to imprint information on the sample surface, for example, by field-emission electrons.

[0004] In the case of a scanning probe microscope (SPM), the tip is used to detect the interaction between the tip and the surface, and to characterize various interactions with the sample down to the atomic level. The measured interaction forces are used to characterize interfaces such as solid-liquid interfaces in correspondence with the material properties of the surface.

[0005] Micromechanical beams can be used in parallel for high-throughput probe topology measurements, lithography, electrical measurements, or detection of a wide range of masses, liquids, viscosities, etc.

[0006] To enable high-speed measurements and minimize wear on the micromechanical beam tip, operation is typically performed in non-contact mode. In non-contact mode, the van der Waals force between the tip and the sample is detected by driving the vibration of the micromechanical beam at its resonant frequency and bringing the micromechanical beam close to the probe surface. Typical beam oscillation amplitudes are in the range of less than 1 nm. Lock-in techniques are usually applied to control the beam vibration. To obtain high-resolution images, the lock-in bandwidth must be several steps higher than the beam's mechanical bandwidth. Typically, the scanning speed in non-contact mode is limited by the time required for the vibrating micromechanical beam to adapt to changes in surface topology associated with the movement of the probe tip over the surface.

[0007] Typically, beam bending when the tip approaches or contacts a surface is detected by reflecting the laser light off a micromechanical beam and measuring the direction of the laser light with a split photodetector. This bending of the micromechanical beam indicates the interaction force between the tip and the sample. This probe measurement technique is called optical reading or optical beam deflection (OBD) reading. Optical reading is the most common method of beam deflection detection, but it is limited by diffraction in the micromechanical beam, which prevents the miniaturization of conventional scanning probes into a single micrometer. [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, there is a need to provide a scanning beam design that enables high-quality, high-resolution measurements by rapidly scanning a surface, as well as a method for fabricating such a beam. [Means for solving the problem]

[0009] This disclosure provides a micromechanical beam for scanning probe measurement, lithography, and the like, which extends longitudinally between a fixed end and a free end. The beam has a height along a height direction perpendicular to the longitudinal direction, and the height is smaller than the width along the width direction. Furthermore, the beam has a bend at the fixed end in the longitudinal direction of the beam, and a reinforcing portion provided between the longitudinal bend and the free end. The beam has a base element and a reinforcing structure provided on the base element within the reinforcing portion, the reinforcing structure configured to increase the bending stiffness of the beam within the reinforcing portion with respect to bending in the height direction.

[0010] This disclosure is based on the insight that the mechanical bandwidth at the beam's resonant frequency limits the measurement speed and scanning resolution. The higher the beam's mechanical bandwidth, the faster it responds to topographic differences and is more suitable for high-speed measurements than beams with low mechanical bandwidth. Therefore, a high mechanical bandwidth increases the detection speed and scanning speed.

[0011] The mechanical bandwidth of a beam is determined by the spring constant and the effective mass of the beam, in addition to external influences such as the surrounding medium that causes beam attenuation and the stiffness of the sample at the position where the beam is scanning. The bandwidth increases as the effective mass decreases. Therefore, the bandwidth can be increased by decreasing the effective mass of the beam, and the scanning speed can also be increased. The ratio of the spring constant to the effective mass is also proportional to the resonant frequency of the beam. Therefore, the higher the resonant frequency, the faster the scanning speed. The reinforcing structure according to this disclosure increases the ratio of stiffness to beam mass while simultaneously decreasing the beam mass while maintaining constant stiffness.

[0012] Increasing the mechanical bandwidth of a beam while keeping the resonant frequency constant is equivalent to increasing the relative damping of the beam's vibrational motion. Beam damping can be characterized by a dimensionless parameter Q, also known as the quality factor or Q value. It represents the rate of energy conversion in the system and is proportional to the ratio of energy deposited within the system to energy loss over the vibrational period. The quality factor Q is generally given by dividing the resonant frequency by the resonant bandwidth at half energy, i.e., Q = f res It is defined as / Δf. The mechanical bandwidth of the beam (f res The Q-value (defined as / Q) can be increased, for example, by reducing the beam dimensions and / or by using lighter materials for the beam. The reduction in effective mass made possible by the reinforcing structure can correspond to a reduction of at least one order of magnitude in the Q-value, such that the mechanical bandwidth is significantly increased.

[0013] The reinforcing portion, and by extension the reinforcing structure, is provided between the free end and the fixed end of the beam. Therefore, bending of the beam occurs mainly at the bent portion at the fixed end of the beam, and bending is suppressed in the remaining free-standing portion of the beam. This concentration of bending at the bent portion increases the stress within the bent portion. For this reason, the bent portion is particularly suitable as a location for installing a reading structure sensitive to local stress in the beam, such as a piezoresistive reading structure.

[0014] In a configuration without the reinforcing structure, the stress induced by the bending of the beam is distributed along the entire length of the beam. However, the reinforcing structure only allows the beam to be bent between the fixed end and the leading edge of the reinforcing portion, and does not substantially deform itself. The stress in the bending region of the beam in a configuration with the reinforcing structure is at least 9 times, for example, at least 12 times, at least 15 times, and at least 18 times higher than in a configuration without the reinforcing structure. For example, the stress in the beam in a configuration with the reinforcing structure is 18.7 times higher than the stress in the beam in a configuration without the reinforcing structure.

[0015] Compared to the beam without the reinforcing structure, the reinforcing structure reduces the mass of the beam while keeping its rigidity constant, and increases its rigidity while keeping its mass constant. Furthermore, the reinforcing structure concentrates the stress on the beam during bending within the bent portion. This increases the sensitivity of stress-based measurement schemes, such as piezoresistive readings, performed in the bent region.

[0016] In summary, by providing the reinforcing structure within the reinforcing portion of the beam, high-speed scanning and highly sensitive reading of beam vibrations are achieved.

[0017] The beam comprises a probe structure provided at the free end of the beam. The probe structure is configured to interact with a sample surface adjacent to the beam. For example, the probe structure is composed of a sharp tip or a cylindrical portion. The probe structure may include a crystalline material. For example, the probe structure may include the material of the beam. The probe structure may include a material different from the material of the beam, or may consist of the material of the beam. For example, the probe structure may include soft materials such as molecules and / or biological materials. The probe structure may be composed of hard materials such as diamond or gallium nitride.

[0018] The longitudinal direction, width direction, and height direction are orthogonal to each other. The length of the beam in the longitudinal direction may be greater than the height and / or width of the beam. The beam is made of a plate, and its height may be, for example, at least one-tenth, one-twenty-fifth, one-fiftieth, or one-hundredth of the length and width.

[0019] The beam is generally configured to vibrate in the height direction. The resonance frequency of the first bending mode of the beam in the height direction is at least 30 kHz, for example at least 40 kHz, 50 kHz, 55 kHz, or 60 kHz. Additionally or alternatively, the resonance frequency of the first bending mode is 10 MHz or less, for example 5 MHz or less, 2 MHz or less, 500 kHz or less, 400 kHz or less, 300 kHz or less, 275 kHz or less, or 250 kHz or less.

[0020] The fixed end of the beam may be fixed to a support structure. The height of the support structure along the height direction is greater than that of the beam. The beam and the support structure may be made of the same material. For example, the beam may be integrally formed with the support structure. Alternatively, the support structure may be separated from the beam by an intermediate layer. For example, the support structure and the beam may be formed of silicon, and the intermediate layer may be composed of a silicon oxide layer.

[0021] The base element may have a rectangular cross-section perpendicular to the longitudinal direction over the entire reinforcement. The base element may have a constant height in the height direction over the entire reinforcement. Additionally or alternatively, the height of the reinforcement structure can be made constant over the entire reinforcement.

[0022] The beam can include a base material such as silicon or diamond. The base element within the reinforcement may include or consist of the base material. Further, the support structure may also include or consist of the base material.

[0023] The beam may include a base element within the bent portion. The base element of the bent portion may be formed of the base material. The height of the base element of the bent portion may be equal to the height of the base element of the reinforcement. The base element of the bent portion may be integrally formed with the base element of the reinforcement.

[0024] The longitudinal length of the beam is at least 20 μm, for example, at least 30 μm, or at least 40 μm. The length of the beam is 500 μm or less, for example, 450 μm or less, 400 μm or less, or 350 μm or less. For example, the length is 150 μm or more and 400 μm or less. The length is 150 μm or more and 170 μm or less, for example, 165 μm, or 325 μm or more and 375 μm or less, for example, 350 μm.

[0025] The longitudinal length of the reinforcing structure is at least 0.25 times the longitudinal length of the beam, for example, at least 0.3 times, at least 0.4 times, at least 0.45 times, or at least 0.5 times. The longitudinal length of the reinforcing structure is 0.75 times or less the longitudinal length of the beam, for example, 0.7 times or less, 0.6 times or less, 0.55 times or less, or 0.5 times or less. A reinforcing structure having such a length provides, on the one hand, a sufficient increase in the rigidity of the beam, and on the other hand, integrates the structure added along the longitudinal range of the beam.

[0026] The length of the reinforcing structure is 10 μm or more and 300 μm or less, for example, 15 μm or more and 200 μm or less, or 15 μm or more and 60 μm or less. For example, the length of the reinforcing structure is 50 μm or more and 250 μm or less. The length of the reinforcing structure is 40 μm or more and 360 μm or less, for example, 75 μm or more and 270 μm or less, or 80 μm or more and 200 μm or less. The length of the reinforcing structure is 40 μm or more and 160 μm or less, for example, 75 μm or more and 100 μm or less, or 80 μm or more and 95 μm or less. The length of the reinforcing structure is 90 μm or more and 360 μm or less, for example, 135 μm or more and 270 μm or less, or 160 μm or more and 200 μm or less.

[0027] The width in the width direction of the reinforcing structure is at least 0.2 times the minimum width of the base element in the reinforcing portion, for example, at least 0.3 times, at least 0.4 times, at least 0.5 times, at least 0.55 times, at least 0.6 times, at least 0.7 times, at least 0.75 times, at least 0.8 times, or at least 0.85 times. The width in the width direction of the reinforcing structure is at least 0.2 times the maximum width of the base element in the reinforcing portion, for example, at least 0.3 times, at least 0.4 times, at least 0.5 times, at least 0.55 times, at least 0.6 times, at least 0.7 times, at least 0.75 times, at least 0.8 times, or at least 0.85 times. For example, the width of the reinforcing structure is 0.8 to 0.95 times, or 0.85 to 0.9 times, for example 0.88 times, the minimum width of the base element in the reinforcing portion, and / or 0.5 to 0.7 times, or 0.55 to 0.65 times, for example 0.6 times, the maximum width of the base element in the reinforcing portion.

[0028] The width of the reinforcing structure is 10 μm or more and 240 μm or less, for example, 15 μm or more and 150 μm or less, or 15 μm or more and 40 μm or less. The width of the reinforcing structure is 35 μm or more and 240 μm or less, for example, 50 μm or more and 180 μm or less, or 65 μm or more and 130 μm or less. The width of the reinforcing structure is 60 μm or more and 240 μm or less, for example, 90 μm or more and 180 μm or less, or 110 μm or more and 130 μm or less. The width of the reinforcing structure is 35 μm or more and 140 μm or less, for example, 50 μm or more and 105 μm or less, or 65 μm or more and 75 μm or less.

[0029] The longitudinal length of the bent portion is at least 0.05 times the longitudinal length of the beam, for example, at least 0.06 times, at least 0.07 times, at least 0.08 times, at least 0.09 times, or at least 0.1 times. The length of the bent portion is 0.4 times or less the longitudinal length of the beam, for example, 0.3 times or less, 0.2 times or less, 0.15 times or less, or 0.11 times or less. A bent portion having such a length provides sufficient flexibility on the one hand, and on the other hand, provides concentration of stress induced by the bending in an area suitable for efficient reading.

[0030] The length of the bent portion is 2.5 μm or more and 80 μm or less, for example, 2.5 μm or more and 30 μm or less. For example, the length of the bent portion is 5 μm or more and 15 μm or less. The length of the bent portion is 10 μm or more and 80 μm or less, for example, 15 μm or more and 60 μm or less, or 18 μm or more and 45 μm or less. The length of the bent portion is 20 μm or more and 80 μm or less, for example, 30 μm or more and 60 μm or less, or 35 μm or more and 45 μm or less. The length of the bent portion is 10 μm or more and 40 μm or less, for example, 15 μm or more and 30 μm or less, or 18 μm or more and 25 μm or less.

[0031] According to one embodiment, the reinforcing structure is provided on the surface of the base element substantially perpendicular to the height direction. This provides more efficient reinforcement of the beam at the reinforcing portion compared to other surfaces.

[0032] According to the embodiment, the reinforcing structure and the probe structure are provided on the same surface of the base element. This makes it possible to fabricate both the reinforcing structure and the probe structure from the same side of the base element, facilitating the fabrication of the micromechanical beam.

[0033] According to one embodiment, the reinforcing structure protrudes from the base element as a self-supporting structure. Such a self-supporting structure provides efficient reinforcement.

[0034] According to one embodiment, the beam comprises a passivation layer provided on the surface of the beam. The reinforcing structure comprises, for example, the same material as the passivation layer. For example, the reinforcing structure is formed by constructing the passivation layer. The material of the passivation layer is, for example, silicon nitride or Si3N4 and / or silicon oxide or SiO2.

[0035] According to the embodiment, with respect to the height-direction bending in the reinforced portion, the bending stiffness of the base element with the reinforcing structure is, for example, at least 1.2, 2.5, 5, 8, 10, 15, or 20 times greater than the bending stiffness of the base element without the reinforcing structure. This increase in stiffness significantly reduces the mass of the beam and significantly increases the bandwidth. The bending stiffness of the base element without the reinforcing structure may be the bending stiffness of the base element within the reinforced portion.

[0036] According to the embodiment, the bending stiffness of the beam with respect to bending in the height direction is at least 1.1 times, for example, at least 1.2 times, at least 1.4 times, at least 1.5 times, at least 2 times, at least 2.5 times, or at least 4 times higher in the reinforced portion than in the bent portion. Such a ratio of bending stiffness in the reinforced portion and the bent portion allows the stress caused by vibration of the beam to be effectively concentrated in the bent portion, which has lower stiffness than the reinforced portion.

[0037] According to the embodiment, the second moment of area of ​​the cross-section of the base element and the reinforcing structure in a plane perpendicular to the longitudinal direction with respect to bending around an axis parallel to the width direction is, for example, at least 5 times, at least 10 times, at least 12 times, or at least 13 times greater than the second moment of area of ​​a rectangle having the same width as the base element and the same area as the cross-section of the base element and the reinforcing structure in the plane perpendicular to the longitudinal direction. Compared to a beam with a rectangular cross-section, the increase in the second moment of area of ​​the beam according to this disclosure significantly reduces the size and mass of the beam without reducing its rigidity. For smaller and lighter beams, the bandwidth is significantly increased compared to a rectangular beam. The second moment of area may also be called the moment of inertia or the moment of inertia of the cross-section.

[0038] Alternatively, or in addition, the second moment of area about the axis of the cross-section of the base element and the reinforcing structure in the plane perpendicular to the longitudinal direction with respect to bending about the axis parallel to the width direction is, for example, at least 1.05 times, at least 1.1 times, at least 1.15 times, or at least 1.2 times the magnitude of the second moment of area about the axis of the cross-section of the base element alone in the reinforcing portion in the plane perpendicular to the longitudinal direction.

[0039] According to the embodiment, with respect to bending about an axis parallel to the width direction, the second moment of area about an axis perpendicular to the longitudinal direction of the cross-section of the beam is, for example, at least 1.1 times, 1.15 times, 1.2 times, 1.25 times, 1.3 times, or 1.4 times greater in the reinforced portion than in the bent portion. This allows the stress caused by vibration of the beam about an axis parallel to the width direction to be effectively concentrated in the bent portion, and facilitates readings based on vibration stress in the bent portion.

[0040] According to the embodiment, the area of ​​the cross-section of the base element and the reinforcing structure in a plane perpendicular to the longitudinal direction is smaller than the area of ​​a rectangle having the same width as the base element and having the same second moment of area about the same axis as the cross-section of the base element and the reinforcing structure in the plane perpendicular to the longitudinal direction, for example, at least 1 / 1.05, 1 / 1.08, or 1 / 1.1. As the area is reduced, the mass of the beam according to this disclosure is smaller and the bandwidth is larger compared to a rectangular beam. Therefore, faster scanning is possible.

[0041] According to the embodiment, the height of the reinforcing structure in the height direction is at least 0.1 times, for example, at least 0.2 times, at least 0.25 times, at least 0.5 times, or at least 1 time, the height of the base element in the height direction. The greater the height of the reinforcing structure, the greater the rigidity of the beam within the reinforcing portion. This makes it possible to reduce the mass without reducing the rigidity of the beam. The height of the reinforcing structure is at least 0.05 μm, at least 0.1 μm, at least 0.25 μm, at least 0.5 μm, at least 1 μm, at least 2 μm, at least 5 μm, or at least 10 μm.

[0042] The height of the reinforcing structure is 1 or less, 1.5 or less, 2 or less, 2.5 or less, or 5 or less than the height of the base element.

[0043] For example, the height of the reinforcing structure is 2.5 μm or less, 3 μm or less, 3.5 μm or less, 4 μm or less, 5 μm or less, 6 μm or less, 10 μm or less, 15 μm or less, 20 μm or less, or 40 μm or less.

[0044] The height of the reinforcing structure is 0.7 μm or more and 5 μm or less. The height is at least 0.7 μm, at least 1 μm, at least 1.5 μm, at least 2 μm, at least 2.5 μm, at least 3 μm, at least 3.5 μm, at least 4 μm, or at least 4.5 μm. The height is 1 μm or less, 1.5 μm or less, 2 μm or less, 2.5 μm or less, 3 μm or less, 3.5 μm or less, 4 μm or less, 4.5 μm or less, or 5 μm or less.

[0045] The Young's modulus of at least one material layer of the reinforcing structure, or the Young's modulus of the reinforcing structure, is at least 100 GPa, for example, at least 150 GPa, at least 200 GPa, at least 250 GPa, at least 300 GPa, at least 350 GPa, or at least 400 GPa. For example, the Young's modulus of a material layer made of tungsten is 411 GPa, and the Young's modulus of a material layer made of molybdenum is 330 GPa. For example, the height of the material layer is at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the height of the reinforcing structure.

[0046] The Young's modulus of at least one material layer of the reinforcing structure, or the Young's modulus of the reinforcing structure, is at least 3.5 times, for example, at least 4 times, at least 4.5 times, at least 5 times, at least 5.5 times, at least 6 times, at least 6.5 times, or at least 7 times, the Young's modulus of the base material of the base element. This efficiently increases the rigidity of the micromechanical beam within the reinforcing portion.

[0047] According to one embodiment, the reinforcing structure comprises at least one ridge extending parallel to the longitudinal direction. The longitudinal ridge is an effective means of strengthening the rigidity of the beam against bending perpendicular to the ridge. The ridge increases the viscosity of the beam, thus increasing damping and lowering the Q-factor.

[0048] According to the embodiment, the aspect ratio of the height of the ridge in the height direction to the width of the ridge in the width direction is at least 0.1, for example, at least 0.2, or at least 0.25. As the aspect ratio of the ridge increases, the rigidity of the reinforcing structure also increases, so a ridge with a high aspect ratio provides efficient reinforcement of the beam. The height of the ridge can be equal to the height of the reinforcing structure.

[0049] For example, the aspect ratio is at least 0.5, at least 1, at least 2.5, at least 3, or at least 3.5. For example, the aspect ratio is greater than 2.5.

[0050] The ratio of the width of the protrusion to the height of the base element is at least 0.4, at least 0.8, at least 1.5, at least 2.5, at least 3, or at least 4. In addition or alternatively, the ratio of the width of the protrusion to the height of the base element is 4 or less, 5 or less, 8 or less, 20 or less, or 40 or less. For example, the ratio of the width of the protrusion to the height of the base element is 4.

[0051] The width of the ridge is at least 0.05 μm, at least 0.1 μm, at least 0.25 μm, at least 0.4 μm, at least 0.5 μm, at least 1 μm, at least 2 μm, at least 3 μm, at least 4 μm, or at least 4.5 μm. In addition or alternatively, the width of the ridge is 3 μm or less, 4 μm or less, 4.5 μm or less, 5 μm or less, 6 μm or less, or 10 μm or less. For example, the width of the ridge is 4.5 μm.

[0052] The width of the raised area is 0.7 μm or more and 2 μm or less. The width is at least 0.7 μm, at least 0.8 μm, at least 1 μm, at least 1.25 μm, at least 1.5 μm, or at least 1.75 μm. The width is 0.8 μm or less, 1 μm or less, 1.25 μm or less, 1.5 μm or less, 1.75 μm or less, or 2 μm or less.

[0053] According to one embodiment, the reinforcing structure comprises a plurality of ridges, for example, at least two ridges, that extend parallel to the longitudinal direction and are arranged adjacent to each other along the width direction. This further increases the rigidity of the beam within the reinforcing portion.

[0054] Each ridge may have the same height and / or the same width. The spacing between each ridge, i.e., the width of the gap between each ridge, is at least 0.1 times, at least 0.25 times, at least 0.5 times, at least 0.75 times, or at least 1 time the width of the ridge. In addition or alternatively, the spacing may be 0.5 times or less, 0.75 times or less, 1 time or less, 1.5 times or less, or 2 times or less the width of the ridge.

[0055] The spacing or width of the gaps between each elevation is at least 0.05 μm, at least 0.1 μm, at least 0.25 μm, at least 0.4 μm, or at least 0.5 μm. In addition or alternatively, the width of the gaps is 3 μm or less, 4 μm or less, 6 μm or less, or 10 μm or less.

[0056] The width of the gap is at least 0.75 μm, at least 1 μm, at least 1.25 μm, at least 1.5 μm, at least 1.75 μm, at least 2 μm, at least 2.25 μm, at least 2.5 μm, at least 2.75 μm, or at least 3 μm. The width of the gap is 1 μm or less, 1.25 μm or less, 1.5 μm or less, 1.75 μm or less, 2 μm or less, 2.25 μm or less, 2.5 μm or less, 2.75 μm or less, 3 μm or less, 3.25 μm or less, 3.5 μm or less, 3.75 μm or less, 4 μm or less, 4.25 μm or less, or 4.5 μm or less.

[0057] According to the embodiment, each of the ridges has the same width in the width direction and / or the same height in the height direction. This makes it possible to manufacture the ridges easily and reliably.

[0058] The reinforcing structure comprises one or more ridges. For example, the reinforcing structure comprises at least two, at least four, at least six, at least ten, at least fifteen, at least twenty, at least thirty, at least fifty, at least seventy, or at least ninety ridges. The reinforcing structure comprises two or fewer, four or fewer, six or fewer, ten or fewer, fifteen or fewer, twenty or fewer, thirty or fewer, fifty or fewer, seventy or fewer, ninety or fewer, or 100 or fewer ridges.

[0059] According to one embodiment, adjacent ridges of the reinforcing structure are connected at their staggered longitudinal ends to form a meandering structure. This makes it possible to integrate the ridges with other functional structures of the micromechanical beam. For example, the ridges form part of a conductive structure, or form a support for such a conductive structure on the beam. By connecting the ends of each ridge, a continuous conductive path for energizing the conductive structure is provided.

[0060] The reinforcing structure may have an even number of connected ridges, and both ends of the meandering structure may be located at the same end of the beam, for example, the fixed end of the beam. This makes it possible to connect the conductive structure associated with the reinforcing structure to the power supply at each end of the beam.

[0061] According to the embodiment, the reinforcing structure is a continuous structure that extends continuously from a first end to a second end in a plane perpendicular to the height direction. Such a reinforcing structure is, for example, composed of a meandering structure. It may include meandering ridges that extend continuously from the first end to the second end.

[0062] For example, the first end and / or the second end are located at one end of the reinforcing portion facing the fixed end of the micromechanical beam. For example, the first end and the second end are located at the same end of the reinforcing portion, such as the end of the reinforcing portion facing the fixed end of the micromechanical beam. This allows the conductive structure to be formed as part of the reinforcing structure or on top of the reinforcing structure.

[0063] According to the embodiment, the reinforcing structure forms part of the conductive structure or forms a support for the conductive structure. Thus, the conductive structure provides a continuous conductive path for current flow.

[0064] According to the embodiment, the micromechanical beam comprises a patterned multilayer structure, the patterned multilayer structure comprising the reinforcing structure. For example, the patterned multilayer structure can be uniformly patterned in the height direction, for example, over the entire surface of the micromechanical beam and / or over the entire micromechanical beam, at least within the reinforcing portion. The multilayer structure may be placed on the base element, such as on the surface of the base element. The multilayer structure may be patterned by etching, electroplating, laser cutting, electron beam processing (EBM), etc.

[0065] Such a multilayer structure allows different functional structures to be integrated into the reinforcing structure. For example, the multilayer structure may provide the conductive structure and / or the drive structure.

[0066] The reinforcing structure can be formed from a conductor such as a semiconductor or a metal, or an insulator such as a polymer such as acrylic or parylene. The reinforcing structure may also be composed of a film such as an acrylic film or a parylene film. For example, the reinforcing structure can be formed from silicon, silicon oxide, silicon nitride, a metal, or diamond.

[0067] The reinforcing structure may comprise at least one, some, or all of, a conductor such as a semiconductor or a metal, or an insulator such as a polymer such as acrylic, polyimide, or parylene. The reinforcing structure may comprise a film such as an acrylic film or a parylene film. For example, the reinforcing structure may comprise at least one, some, or all of, silicon, silicon oxide, silicon nitride, metal, and diamond.

[0068] According to the embodiment, the reinforcing structure and the base element are made of at least partially the same material and are integrally joined together. This ensures a secure connection between the base element and the reinforcing structure, and further hardens the beam within the reinforcing portion. For example, at least a portion of the reinforcing structure may be formed by selectively removing a portion of the material forming the base element. This portion may be removed by etching, laser cutting, electron beam processing (EBM), or the like.

[0069] According to the embodiment, the reinforcing structure includes a material different from the base material of the base element. For example, the reinforcing structure consists solely of a material different from the base material of the base element. The material different from the base element is, for example, a metal.

[0070] According to one embodiment, the beam is provided with a conductive metal structure on top of the reinforcing structure, which is DC-separated from the reinforcing structure. Such a metal structure also serves, for example, to heat the beam. In addition or alternatively, the metal structure may be composed of a thermomechanical actuator, such as a bimetallic actuator. The metal structure may be formed of a different material from the reinforcing structure.

[0071] In other embodiments, the reinforcing structure may comprise the conductive metal structure. For example, the reinforcing structure consists of the conductive metal structure.

[0072] The metal structure is DC-separated from the reinforcing structure and / or the base element by an insulating protective layer such as an oxide layer.

[0073] The conductive metal structure may constitute at least a portion of the current loop. It may form a continuous conductive structure extending continuously from a first end to a second end. According to an embodiment with a reinforcing structure having only one ridge, the first end may be located at one end of the reinforcing portion in the longitudinal direction, and the second end may be located at the opposite end of the reinforcing portion. Of these ends, for example, the end further away from the fixed end of the micromechanical beam, the metal structure may be electrically connected to the base element of the micromechanical beam, and the current loop may be closed through the base element. The metal structure may be electrically insulated from the base element along the remainder of the ridge.

[0074] In other embodiments, the reinforcing structure may comprise an even number of ridges arranged adjacent to each other in the width direction and connected at their staggered longitudinal ends. The conductive metal structure may form closed current loops along the ridges, where both ends of the conductive metal structure may be located on the same longitudinal side of the reinforcing portion, for example, the side facing the fixed end of the micromechanical beam.

[0075] The closed current loop can form part of a drive structure that drives the mechanical vibration of the beam.

[0076] The beam may include reinforcing elements within the bent portion. The reinforcing elements are configured to prevent stress accumulation in them, thereby concentrating the stress caused by the bending of the beam in the reading area of ​​the bent portion. The reinforcing elements may be provided on the edges of the beam in the width direction. The reinforcing elements may extend in the longitudinal direction. For example, the reinforcing elements may consist of elongated ridges. Unless otherwise specified, the reinforcing elements have the same configuration as the disclosed reinforcing structures, and vice versa.

[0077] The reinforcing element may have a width greater than the width of the protrusion of the reinforcing structure along the width direction. This increases the stiffening function of the reinforcing element compared to the stiffening function of the protrusion of the reinforcing structure.

[0078] The reinforcing element is separated from the reading region by an opening in the beam. The opening may extend parallel to the reinforcing element. Such an opening further concentrates the strain caused by the bending of the beam into the reading region.

[0079] The width of the opening in the reading structure along the width direction is at least 0.1 times, 0.25 times, 0.5 times, or 1 time the height of the base element in the bent portion. In addition or alternatively, the width of the opening is 0.5 times or less, 1 time or less, 2 times or less, or 5 times or less the height of the base element in the bent portion.

[0080] The width of the opening in the reading structure along the width direction is at least 0.25 μm, at least 0.3 μm, at least 0.4 μm, or at least 0.5 μm. In addition or alternatively, the width is 5 μm or less, 10 μm or less, 20 μm or less, or 50 μm or less.

[0081] According to other embodiments, the micromechanical beam may comprise only the opening and may not comprise the reinforcing element. The opening may extend, for example, parallel to the longitudinal direction of the micromechanical beam. In addition to the opening, the micromechanical beam may comprise an additional opening located on the opposite side of the beam from the opening.

[0082] In addition to the aforementioned reinforcing elements, the beam may be provided with additional reinforcing elements within the bent portion. Unless otherwise specified, the additional reinforcing elements have the same configuration as the disclosed reinforcing elements, and vice versa. These two reinforcing elements may each be provided on opposing edges of the beam within the bent portion. In addition or alternatively, the reading region may be provided between the two reinforcing elements. This allows the strain caused by the bending of the beam to be efficiently concentrated in the reading region.

[0083] A micromechanical beam having one or more reinforcing elements may not have the reinforcing structure and / or the reinforcing portion. Therefore, this disclosure also relates to a micromechanical beam having at least one reinforcing element. All embodiments disclosed for a micromechanical beam having the reinforcing portion also apply to a micromechanical beam having only the reinforcing element.

[0084] According to the embodiment of the beam having the conductive metal structure, the metal structure comprises two leads for power connection that extend longitudinally through the bend. The leads may be mounted on the reinforcing element within the bend. For example, the reinforcing element and / or the additional reinforcing element may mount the leads. According to another embodiment, the leads may also form the reinforcing element.

[0085] According to the embodiment, the plurality of leads are arranged in the edge region of the bent portion. This concentrates the strain caused by the bending of the beam between the leads. The edge region may comprise two sub-regions on opposing edges of the beam extending parallel to or substantially parallel to the longitudinal direction. Each sub-region may comprise one of the plurality of leads. The two sub-regions may be provided on opposing sides of the reading region along the width direction.

[0086] According to the embodiment, the width of the lead within the bent portion is greater than the width of the protrusion of the reinforcing structure. On the other hand, this reduces the resistance of the lead within the bent portion, and therefore also reduces the thermal influence of the lead on the beam within the bent portion. Furthermore, the wider lead increases the rigidity of the beam in the region occupied by the lead.

[0087] The width of the lead is at least 1.2 times, at least 1.5 times, at least 2.0 times, or at least 2.5 times the height of the base element in the bent portion. In addition or alternatively, the width of the lead is at least 1.2 times, at least 1.5 times, at least 2.0 times, or at least 2.5 times or less the height of the base element in the bent portion.

[0088] For example, the width of the lead is at least 0.25 μm, at least 0.3 μm, at least 0.4 μm, or at least 0.5 μm. In addition or alternatively, the width is 2.5 μm or less, 5 μm or less, 10 μm or less, or 15 μm or less.

[0089] According to one embodiment, the metal structure has at least two conductive layers stacked in the height direction to form a thermoactive polymetallic structure configured to cause bending strain in the beam. Thus, the metal structure can also form an actuator that bends the beam in the height direction. For example, the metal structure may be configured to vibrate the beam in the height direction. Each conductive layer may be made of a material having a different coefficient of thermal expansion. The metal structure can also form a thermomechanical actuator.

[0090] According to other embodiments, the metal structure may also comprise only a single metal layer.

[0091] The metal layers of the metal structure, such as the single metal layer, the first metal layer, and the second metal layer, may contain or consist of one of aluminum, tungsten, tungsten alloy, aluminum-magnesium alloy, molybdenum, and molybdenum alloy.

[0092] Tungsten and molybdenum are metallic materials that exhibit excellent durability against thermal and mechanical stress, high resistance to corrosion and wear, a high melting point, retention of mechanical strength at high temperatures, and high hardness at room temperature. The metal layer may be formed by a dual-target or multi-target sputtering deposition method.

[0093] The metal layers, such as the single metal layer, the first metal layer, or the second metal layer, can be formed as polycrystalline layers and / or thin film layers, for example, as polycrystalline tungsten or molybdenum layers and / or thin film tungsten or molybdenum layers.

[0094] The metal layer, such as a tungsten or molybdenum polycrystalline layer and / or thin film layer, may be formed by dry etching, for example by reactive ion etching, in a mixed gas of, for example, SF6 and SF6,+N+CHF3. The electron energy during etching is 100 eV, 75 eV, or 50 eV or less, or 100 eV, 75 eV, or less than 50 eV. Such energies provide small undercuts at the edges of the metal layer.

[0095] The thermal expansion coefficient of at least one metal layer, e.g., each metal layer, differs from the thermal expansion coefficient of the base layer substrate by only 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% or less. This matches the thermal expansion coefficients of the metal layer and the substrate that prevent damage to the cantilever due to thermal stress. Furthermore, the thermal expansion coefficient of at least one metal layer, e.g., each metal layer, differs from the thermal expansion coefficient of the base layer substrate by only 2.5%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. This provides efficient driving of the bending of the micromechanical beam upon heating of the metal layer, for example, upon resistance heating of the metal layer.

[0096] According to one embodiment, the reinforcing structure is formed by etching the base element using the metal structure as an etch mask. This eliminates the need to define an etch mask specifically for the production of the reinforcing structure, thereby enabling cost-effective production of the beam.

[0097] According to the embodiment, the beam has a further reinforcing structure provided within the reinforcing portion and positioned on a further surface of the base element of the beam, wherein the surface and the further surface are parallel to each other and located on opposite sides of the base element in the height direction. The further reinforcing structure further increases the rigidity of the beam in addition to the reinforcing structure.

[0098] The further reinforcing structure may comprise one or more longitudinal ridges extending parallel to each other along the longitudinal direction. The one or more ridges may be provided on the longitudinal edges of the beam. For example, the further reinforcing structure may comprise two ridges provided on opposing longitudinal edges of the beam.

[0099] According to the embodiment, the beam has a reading structure for measuring the mechanical vibration of the beam in the height direction, the reading structure being, for example, a piezoresistive reading structure and / or a Wheatstone bridge, and the reading structure being provided in the bent portion of the beam. The reinforcing structure concentrates the stress caused by the bending of the beam in the height direction in the bent region. Therefore, by placing the reading structure within the bent portion, the sensitivity of reading the bending of the beam is increased.

[0100] The reading structure can consist of a piezoresistive reading structure and / or a strain-sensing reading structure such as a Wheatstone bridge. Compared to optical reading, the strain-sensing reading structure can be integrated into a smaller area than the area required for the reflection of laser light from the surface of the micromechanical beam. For example, optical reading requires a minimum reflective area on the back of the beam. In high-end systems, this area is 3 μm × 9 μm in size, requiring a small laser spot. Compared to reading structures mounted directly on the surface of the beam, optical reading methods require access to bulky optical components, their mechanical adjustments, and very precise mechanical alignment. Optical components are usually bulky and take up space, increasing the physical dimensions of the instrument. This makes high-speed scanning with very small beams (1 μm × 3 μm) and operation in closed vacuum or cryogenic chamber environments difficult. Thus, mounting the reading structure directly on the beam allows for further miniaturization of the beam.

[0101] Generally, reading structures composed of stress-sensitive structures serve as an alternative to OBD readings, providing imaging in diverse environments such as vacuum, air, and liquids. Stress-sensitive structures measure beam deflection via stress induced within the beam within the sensor region. This stress is proportional to the beam thickness. The thicker the beam, the higher its rigidity (e.g., exceeding 100 N / m). Such beams are typically unsuitable for imaging soft samples such as polymers and biological materials. Thick beams usually require large forces between the probe structure and the sample, often leading to wear or breakage of the probe structure.

[0102] The sensitivity of the stress-sensitive structure to beam deflection, i.e., the minimum deflection that can be measured, depends on the stress generated within the reading structure, for example, within a Wheatstone bridge circuit. Therefore, the reading structure is positioned in the region of maximum stress, i.e., on the upper or lower surface of the beam within the bend provided at the fixed end of the beam. Furthermore, the stress-sensitive reading structure is suitable for beams in which high stress is induced by beam deflection or bending. By reinforcing the beam with the reinforcing structure between the free end and the reading structure, high stress can be obtained without increasing the spring constant of the beam within the bend. This makes it possible to form a beam that is sensitive to small forces and / or loads. For example, the beam is subjected to a 10-degree stress acting between the probe structure and the sample. -15 N and 10 -18 It can be configured to detect the force between N and the target.

[0103] The reading structure may comprise a Wheatstone bridge having a resistor made of a piezoresistive material. The Wheatstone bridge may be a full Wheatstone bridge. The resistor may be made as a thin-film resistor. The reading structure may surround an opening in the beam. Such an opening can further concentrate the stress in the resistive region of the reading structure.

[0104] The beam may have, in addition to or as an alternative to, the opening surrounded by the Wheatstone bridge, one or more additional openings located adjacent to the reading structure. For example, the one or more additional openings may consist of longitudinal openings or slots. They may extend parallel to the longitudinal direction. Each additional opening may be located between the longitudinal edge of the beam and the reading structure. For example, the beam may have additional openings located on both sides of the widthwise side of the reading structure, positioned between the longitudinal axis of the beam and the reading structure.

[0105] The opening surrounded by the reading structure and / or the additional opening may be configured to reduce the rigidity within the reading structure by 5% or less, 2.5% or less, 1% or less, for example by 1%, compared to the same beam without the opening. Furthermore, the opening may be configured to increase the sensitivity of the reading structure by at least 5% or at least 7.5% or at least 10%, for example by 10%, compared to the same beam without the opening.

[0106] The reading structure may have a bandwidth of at least 10 kHz, at least 15 kHz, or at least 20 kHz, for example, 50 kHz. The vertical resolution of the reading structure may be 0.1 nm to 25 nm, for example, 0.1 nm to 15 nm, for example, 12 nm. The reading structure may be configured to detect thermally induced vibrations of the beam in air and / or liquid and / or vacuum during resonances not caused by external operation.

[0107] According to one embodiment, the reading structure can be provided between the two leads of the metal structure. This allows the stress induced by the bending of the beam to be further concentrated in the region of the reading structure.

[0108] According to one embodiment, the beam has at least one transverse notch within the bent portion. Such a transverse notch allows the stress induced by the bending of the beam to be further concentrated in a region facing the center of the beam. The transverse notch may be provided on the longitudinal edge of the beam.

[0109] With respect to the length of the notch parallel to the longitudinal direction and the width of the notch parallel to the width direction, the ratio of the width to the length can be at least 0.5, at least 0.75, at least 0.8, at least 0.9, or at least 0.95. Furthermore, the ratio of the width to the length can be 2.0 or less, 1.5 or less, 1.25 or less, 1.1 or less, or 1.05 or less.

[0110] The notch can be tapered along the width direction. For example, the notch parallel to the longitudinal direction may be longer near the edge of the beam than near the center of the beam. The ratio of the width to the length of the notch may be applied to the length of the notch at the edge of the beam.

[0111] According to the embodiment, the beam has two transverse notches on the sides of the beam that face each other in the width direction at the bent portion.

[0112] The width of the beam is narrowed by the one or two lateral notches to 0.85 times or less the maximum lateral width of the beam within the bend, for example, 0.8 times or less, 0.75 times or less, 0.7 times or less, or 0.5 times or less.

[0113] According to the embodiment, the width of the beam in the notch is deviated from the minimum width by less than 20%, for example less than 10%, less than 5%, or less than 1%, over a longitudinal length at least equal to the longitudinal length of the reading structure. Such a notch narrows the beam over the entire length of the reading structure in the longitudinal direction, so that stress induced by the bending of the beam can be efficiently concentrated in the reading structure.

[0114] This disclosure also generally relates to micromechanical beams having at least one transverse notch within the bend and lacking the reinforcing structure. All other embodiments disclosed relating to micromechanical beams featuring the reinforcing structure according to this disclosure also apply to micromechanical beams having only the at least one transverse notch and lacking the reinforcing structure.

[0115] According to one embodiment, the beam is equipped with a drive structure configured to excite the mechanical vibration of the beam in the height direction, and the drive structure is provided in the reinforcing section. The beam with the drive structure is suitable for active sensing, and the interaction between the probe structure of the beam and the sample is detected by the shift in the resonant frequency of the beam during drive oscillation. The beam can be miniaturized by directly mounting the drive structure on the beam. Furthermore, by equipping the drive structure, a large beam array can be used without taking up much space, enabling a very compact measurement configuration. By installing the drive structure in the reinforcing section between the free end and the fixed end of the beam, the vibration can be efficiently driven by the drive structure.

[0116] The drive structure may consist of a thermomechanical actuator. It may comprise a multilayer structure comprising at least two layers of materials having different coefficients of thermal expansion. Due to the different coefficients of thermal expansion of these layers, they expand at different rates, causing the beam to bend. This makes it possible to control the displacement of the beam by the power dissipated into the embedded resistance formed by the lamination. The drive structure may comprise at least two thin film layers.

[0117] The drive structure may be formed of a conductive metal structure, such as a conductive metal structure on the reinforcing structure. Alternatively, the drive structure may be formed of the reinforcing structure itself. The reinforcing structure may also comprise the drive structure.

[0118] The aforementioned drive structure can be configured to allow control of temperature changes, such as heating itself, by internal temperature control such as conductive and / or resistive energy transfer, or external temperature control such as heat dissipation energy transfer. Thermomechanical operation is also called bimorph drive.

[0119] Generally, the beam is configured to vibrate at or near its resonant frequency, and this vibration is driven by the drive structure to provide the relative vibrational motion of the beam's probe structure across the sample surface. When the beam vibrates relative to the sample surface, the vibration amplitude and phase of the beam are modulated by the interaction between the beam and the sample. A feedback signal is generated, for example, by the reading structure, in response to the interaction between the tip and the sample. The beam may be configured to maintain a constant vibration amplitude and phase during scanning using the feedback signal. These feedback signals are used to determine the characteristics of the sample surface.

[0120] According to one embodiment, the reinforcing structure is formed from a material different from the material of the drive structure.

[0121] According to one embodiment, the beam has at least one longitudinal slot extending over the length of the bend. The longitudinal slot may form an opening or additional opening that extends within the reading portion parallel to the reinforcing element and / or adjacent to the reading structure, for example, between the reading structure and the edge of the beam.

[0122] According to the embodiment, in the reinforcing portion, the beam tapers along the longitudinal direction by at least 0.1 times, for example, at least 0.2 times, or at least 0.25 times, in the width direction. For example, the beam tapers towards its free end. As a result, the mass of the beam concentrates towards its fixed end, and the bandwidth of the beam increases.

[0123] This disclosure also generally relates to mechanical beams that have a taper along the longitudinal direction and do not have the reinforcing structure. All other embodiments disclosed relating to micromechanical beams featuring the reinforcing structure according to this disclosure also apply to micromechanical beams that have only the taper and do not have the reinforcing structure.

[0124] This disclosure also covers a detection system comprising a micromechanical beam and a control system coupled to the micromechanical beam. The control system may include an actuation module and / or a reading module.

[0125] The actuation module may be coupled to the drive structure and / or configured to drive the bending of the beam by the drive structure. For example, the drive structure may be configured to generate alternating current and / or pulsed current that is sent to the drive structure, for example, through the leads of the metal structure forming the drive structure. The leads may extend through the bent portion of the beam.

[0126] The reading module may be coupled to the reading structure and configured to determine the bending of the beam by the reading structure. For example, the reading module may be configured to detect stress within the bending portion by the reading structure. For this reason, the reading module may be configured to detect changes in resistance within the Wheatstone bridge and determine the bending of the beam from that resistance.

[0127] The control system may include a scanning module configured to bring about relative movement between the beam and the sample. The scanning module may include, for example, a mechanical actuator. The scanning module may be configured to move the beam relative to the sample in the width direction and / or the longitudinal direction and / or the height direction, and / or to move the sample relative to the beam.

[0128] The control system may be configured to control the operation of the beam by the actuation module and / or to receive information about the bending of the beam from the reading module. The control module may be configured to drive the vibration of the beam via the actuation module. The frequency of the vibration may be swept over the mechanical resonance of the bending motion of the beam. The control module may further be configured to determine the amplitude and / or phase of the vibration of the beam from the information received via the reading module and to generate a feedback signal to control the motion of the beam so as to keep the amplitude and / or phase of the vibration constant. Furthermore, the control module may be configured to move the beam relative to the sample via the scanning module and output a feedback signal generated by the movement.

[0129] Furthermore, this disclosure relates to a method for producing a micromechanical beam, the method being: - To provide the substrate for the beam, - To create a reinforcing structure on the surface of the substrate perpendicular to the height direction, - This includes preparing a self-supporting beam from the substrate, The beam extends longitudinally between a fixed end and a free end. The beam has a height along the height direction perpendicular to the longitudinal direction, and the height is smaller than the width along the width direction. The beam has a bent portion provided at the fixed end in the longitudinal direction of the beam, and a reinforcing portion provided between the bent portion in the longitudinal direction and the free end. The reinforcing structure is provided within the reinforcing portion, The method also includes a method in which the reinforcing structure is configured to increase the bending rigidity of the beam within the reinforcing portion with respect to bending in the height direction.

[0130] The micromechanical beam may be the micromechanical beam described herein. All embodiments and technical effects disclosed relating to the micromechanical beam also apply to the method, and vice versa.

[0131] According to the embodiment, the reinforcing structure is manufactured by - To provide a metal structure having two leads for power connection on the surface of the substrate, - This includes etching the substrate parallel to the height direction using the metal structure as an etching mask.

[0132] Furthermore, this disclosure also covers a method for detecting a sample using a micromechanical beam relating to this disclosure. The method includes placing the beam, for example, the probe structure of the beam, next to the sample; driving the vibration of the beam; and detecting changes in the vibration due to the interaction between the sample and the beam. The method can be performed by the control system relating to this disclosure. All embodiments and technical effects disclosed for the control system also apply to the detection method, and vice versa.

[0133] The detection of the aforementioned change in vibration may include detection to determine the shift in the resonant frequency of the vibration induced by the interaction between the sample and the beam.

[0134] The method may include driving the bending of the beam by the drive structure. For example, the method may include generating an alternating current and / or a pulsed current and sending the current to the drive structure, for example, through the leads of the metal structure forming the drive structure.

[0135] The method may include determining the bending of the beam. For example, the method may include detecting the stress induced by the bending. The method may also include detecting a change in resistance within the Wheatstone bridge and determining the bending of the beam from the change in resistance.

[0136] The method may include causing relative movement between the beam and the sample. The method may also include moving the beam relative to the sample and / or moving the sample relative to the beam.

[0137] The method may include controlling the operation of the beam and / or receiving information regarding the bending of the beam. The method may also include driving the vibration of the beam. The frequency of the vibration may be swept across the mechanical resonance of the bending motion of the beam. The method may include determining the amplitude and / or phase of the vibration of the beam and generating a feedback signal to control the motion of the beam so as to keep the amplitude and / or phase of the vibration constant. Furthermore, the method may include moving the beam relative to a sample and outputting the feedback signal generated by the movement.

[0138] Each of the beams relating to this disclosure is also called a cantilever.

[0139] The embodiments and functions of this disclosure will be described illustratively below with reference to the drawings. The drawings schematically illustrate the contents described below. [Brief explanation of the drawing]

[0140] [Figure 1] Side view of a micromechanical beam relating to prior art. [Figure 2] Cross-sectional view of the micromechanical beam shown in Figure 1. [Figure 3] A diagram showing a first embodiment of the micromechanical beam relating to this disclosure. [Figure 4] Cross-sectional view of the micromechanical beam shown in Figure 3. [Figure 5] A further cross-sectional view of the micromechanical beam shown in Figure 3. [Figure 6] A perspective view of another embodiment of the micromechanical beam relating to this disclosure. [Figure 7] Cross-sectional view of an embodiment of the micromechanical beam according to this disclosure. [Figure 8] A diagram illustrating the bending of a micromechanical beam without a reinforcing structure. [Figure 9] A diagram illustrating the bending of a micromechanical beam equipped with a reinforcing structure. [Figure 10] Detailed top view of the reading area of ​​the micromechanical beam relating to this disclosure. [Figure 11] A diagram showing the stress applied to the reading area of ​​a micromechanical beam with a rectangular cross-section. [Figure 12] A figure showing the differential output voltage of the reading structure as a function of the deflection of the micromechanical beam relating to this disclosure. [Figure 13] A diagram showing the differential output voltage of a reading structure as a function of the deflection of a micromechanical beam with a rectangular cross-section. [Figure 14] A figure showing the response of the output voltage of the reading structure to the instantaneous deflection of the micromechanical beam relating to this disclosure, as a function of time. [Figure 15]A figure showing the first precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 16] A figure showing the second precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 17] A figure showing the third precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 18] A figure showing the fourth precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 19] A figure showing the fifth precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 20] A figure showing the sixth precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 21] A figure showing the seventh precursor structure obtained by the method for producing a micromechanical beam according to this disclosure. [Figure 22] A diagram showing an array consisting of four micromechanical beams relating to this disclosure. [Figure 23] A diagram illustrating another embodiment of the micromechanical beam relating to this disclosure. [Figure 24] A diagram showing a cross-section perpendicular to the longitudinal direction of an alternative embodiment of the micromechanical beam according to this disclosure. [Figure 25] A plan view of a further embodiment of the micromechanical beam relating to this disclosure. [Figure 26] A diagram showing a cross-section perpendicular to the longitudinal direction of a further alternative embodiment of the micromechanical beam according to this disclosure. [Modes for carrying out the invention]

[0141] Figure 1 shows a side view of a prior art micromechanical beam 200, and Figure 2 shows a cross-sectional view of the micromechanical beam 200 along line AA shown in Figure 1. The micromechanical beam 200 has a free end 22 and a fixed end 20 fixed to a support structure 201. The self-supporting portion of the micromechanical beam 200 extends longitudinally 3 over a length 10 between the fixed end 20 and the free end 22.

[0142] The micromechanical beam 200 has a uniform rectangular cross-section over a length of 10, with a width 11 along the width direction 4 and a height 12 along the height direction 5. The width direction 4 and the height direction 5 are perpendicular to each other and are also perpendicular to the longitudinal direction 3.

[0143] A force F acting on the free end 22 of the micromechanical beam 200, parallel to the height direction 5, bends the micromechanical beam 200 by a distance z along the height direction 5. When the force F acts periodically, the micromechanical beam 200 oscillates around its equilibrium position.

[0144] When the amplitude is small, the vibrating micromechanical beam 200 is equivalent to a spring-mass system defined by its spring constant k and equivalent mass m, and therefore the resonant frequency is given by the following equation.

number

[0145] For the micromechanical beam 200 having a rectangular cross-section as shown in Figure 2, the equivalent spring constant of the first bending mode is expressed by the following equation.

number

[0146] The static deflection z of a uniform micromechanical beam 200 under a lateral force F acting on the free end 22 can be calculated using classical Bernoulli-Euler beam theory. For the rectangular cross-section shown in Figures 1 and 2, the deflection z under force load F is given by the following equation.

number

[0147] Calculating bending forces, such as the bending force generated when a micromechanical beam 200 with a free end 22 approaches the probe surface, requires knowledge of both the mechanical properties of the beam material and the geometric configuration of the micromechanical beam 200, also known as the second moment of area or the moment of inertia I of the cross section. The bending stiffness of the micromechanical beam 200 is the tensor product (E × I) of Young's modulus and the moment of inertia of the cross section. Young's modulus represents the material's properties and is constant over the length 10 of the micromechanical beam 200. For a micromechanical beam 200 with a constant rectangular cross section (hereinafter also referred to as a rectangular beam), the second moment of area is expressed by the following equation.

number

number

[0148] Brownian motion causes spontaneous oscillations in the micromechanical beam 200, and each oscillation mode of the micromechanical beam 200 has the same average thermal energy k B This leads to the presence of T. These thermal fluctuations are called thermomechanical noise. By Fourier transforming the oscillatory motion obtained as a function of time, the power spectral density (PSD) of the motion in the frequency domain can be determined. For example, the Brownian motion of a micromechanical beam 200 in air is caused by surrounding molecules that transfer irregular momentum to the micromechanical beam 200.

[0149] When expressing the mechanics of the micro - mechanical beam 200 as a harmonic oscillator having total system energy, according to the equipartition principle, the average energies of the kinetic energy and the potential energy are both expressed as follows.

Equation

Equation

number

number

[0150] For a micromechanical beam 200 made of silicon, with a length of 5 μm and a cross-section of 10 × 100 nm, the mass m is approximately m ≈ 47 × 10⁻¹⁰. -18 It is kg, and the resonant frequency is approximately f res It is approximately 100MHz, and the average displacement is <z>This is approximately equal to 40 fm. The ground state energy of a beam with a frequency of several hundred MHz can be considered equal to its mK temperature.

[0151] The maximum achievable scanning speed is determined by the maximum achievable speed when the micromechanical beam 200 moves relative to the sample. In the low attenuation limit, the speed is given by the following equation.

number

[0152] In the limit of high damping, the aforementioned velocity is given by the following equation.

number

[0153] In the above, D is damping, S S This represents surface elasticity.

[0154] From the above equation, it can be estimated that if the mass of the micromechanical beam 200 is reduced, such as by making the micromechanical beam 200 smaller, the maximum achievable scanning speed will increase.

[0155] Figure 3 shows a first embodiment of the micromechanical beam 1 according to the present disclosure. Figure 4 shows a cross-sectional view of the micromechanical beam 1 perpendicular to the longitudinal direction 3 along line AA shown in Figure 3, and Figure 5 shows a further cross-sectional view of the micromechanical beam 1 perpendicular to the longitudinal direction 3 along line BB shown in Figure 3. Unless otherwise specified, the micromechanical beam 1 has the same configuration as the micromechanical beam 200 shown in Figures 1 and 2, and vice versa.

[0156] Similar to beam 200, the micromechanical beam 1 extends longitudinally 3 over a length of 10 between a fixed end 20 and a free end 22. The fixed end 20 is integrally connected to the support structure 201 with the same material. The micromechanical beam 1 is equipped with a probe structure 7 at the free end 22. The probe structure 7 is provided within the probe portion 25 of the micromechanical beam 1 as an end projecting in the height direction 5 from the micromechanical beam 1. The height direction 5 is perpendicular to the longitudinal direction 3. Furthermore, the height direction 5 and the longitudinal direction 3 are perpendicular to the width direction 5.

[0157] The micromechanical beam 1 includes a base element 50 that extends from a fixed end 20 to a free end 22. The base element 50 is plate-shaped and has a height 51 along the height direction 5. The height 51 is smaller than either the length 10 parallel to the longitudinal direction 3 or the width 11 of the base element 50 parallel to the width direction 4. The base element 50 is made of silicon and is formed as a single, integrated element made of the same material. The probe structure 7 is provided on the surface 52 of the base element 50 at the free end 22.

[0158] The micromechanical beam 1 has a bent portion 30 in the direct support structure 201 having a length 31 parallel to the longitudinal direction 3. The micromechanical beam 1 has a reinforcing portion 40 extending over a length 41 parallel to the longitudinal direction 3 between the bent portion 30 and the free end 22. The reinforcing portion 40 is located at a distance 49 from the bent portion 30. The width 11 of the base element 50 within the reinforcing portion 40 tapers from a maximum width 56 to a minimum width 57 towards the free end 22 of the micromechanical beam 1. In the embodiment shown in Figure 3, the base element 50 has a straight edge 54 in the region between the maximum width 56 and the minimum width 57.

[0159] The micromechanical beam 1 includes a reinforcing structure 100 within the reinforcing section 40. As shown in Figure 4, the reinforcing structure 100 is provided on the surface 52 of the base element 50, which also supports the probe structure 7. The reinforcing structure 100 is integrally joined to the base element 50 using the same material. Therefore, the base element 50 and the reinforcing structure 100 form a single unit.

[0160] The reinforcing structure 100 comprises a plurality of longitudinal ridges 110. These ridges 110 are parallel to each other along the longitudinal direction 3 and are joined at alternating longitudinal ends 107 to form a meandering structure. The structure extends from the first end 108 to the second end 109.

[0161] As shown in Figure 4, the ridges 110 have a substantially rectangular cross-section in a plane perpendicular to the longitudinal direction 3, and the ridges 110 have a height 102 along the height direction 5 and a width 112 along the width direction 4. Furthermore, the ridges 110 are spaced apart from each other by a distance 122 along the width direction 4, and gaps 120 are formed between each ridge 110. Generally, the height 102 of the reinforcing structure 100 is between 0.25 and 5 times the height 51 of the base element 50.

[0162] The reinforcing structure 100 has a length 101 along the longitudinal direction 3 and a width 104 parallel to the width direction 4. The length 101 of the reinforcing structure 100 is equal to the length 41 of the reinforcing portion 40. The width 104 of the reinforcing structure 100 is smaller than the width 11 of the base element 50 in the reinforcing portion 40.

[0163] The length 101 of the reinforcing structure 100 is 0.5 times the length 10 of the micromechanical beam 1. Generally, the length 101 of the reinforcing structure 100 is between 0.25 and 0.8 times the length 10 of the micromechanical beam 1, for example, between 0.4 and 0.6 times.

[0164] The width 104 of the reinforcing structure 100 is 0.9 times the minimum width 57 of the micromechanical beam 1 in the reinforcing section 40. Generally, the width 104 of the reinforcing structure 100 is between 0.5 and 1 times the minimum width 57 of the micromechanical beam 1 in the reinforcing section 40, for example, between 0.8 and 0.95 times. The width 104 of the reinforcing structure 100 is 0.6 times the maximum lateral width 36 of the micromechanical beam 1. Generally, the width 104 of the reinforcing structure 100 is between 0.3 and 0.8 times the maximum lateral width 36, for example, between 0.5 and 0.7 times.

[0165] The micromechanical beam 1 includes a drive structure 70 separated from the reinforcing structure 100 by an insulating layer 78 on the upper surface 79 of the reinforcing structure 100 facing the opposite side of the base element 50. The insulating layer 78 has a height 73 that is smaller than the height 51 of the base element 50. For example, the height 73 of the insulating layer 78 is between 0.1 and 0.5 times the height 51 of the base element 50, for example, 0.3 times.

[0166] The drive structure 70 has a height 75 that is smaller than the height 51 of the base element 50. For example, the height 75 of the drive structure 70 is between 0.1 and 0.3 times the height 51 of the base element 50, for example, 0.2 times.

[0167] The drive structure 70 is made of metal and constitutes a metallic structure. It comprises a first metal layer 72 adjacent to the insulating layer 78 and a second metal layer 74 positioned on the side of the first metal layer 72 facing the insulating layer 78. The drive structure 70 is configured as a thermomechanical actuator, and the first metal layer 72 and the second metal layer 74 each have different coefficients of thermal expansion.

[0168] The drive structure 70 is resistively heated by the flow of electric current through the meandering drive structure 70. When the drive structure 70 is heated, the first metal layer 72 and the second metal layer 74 expand by different amounts. As a result, the drive structure 70 bends along the height direction 5, and therefore the micromechanical beam 1 also bends along the height direction 5.

[0169] The total height 12 of the micromechanical beam 1 in the reinforcing section 40 is the sum of the height 51 of the base element 50, the height 102 of the reinforcing structure 100, the height 73 of the insulating layer 78, and the height 75 of the drive structure 70. The insulating layer 78 may be an acrylic layer or a parylene layer.

[0170] To connect the drive structure 70 to a power source, the drive structure 70 is provided with two leads 76 that extend from the reinforcing portion 40 through the bending portion 30 to the support structure 201. As shown in Figure 5, each lead 76 has a width 99 parallel to the width direction 4. The width 99 is greater than the width 112 of the protrusion 110 of the reinforcing structure 100.

[0171] The probe portion 25, the reinforcing portion 40, and the bending portion 30 are separated along the longitudinal direction 3 and arranged adjacent to each other along the longitudinal direction 3.

[0172] As shown in Figure 5, each lead 76 is positioned on top of the reinforcing element 97. The reinforcing element 97 is integrally joined to the base element 50 with the same material, so the reinforcing element 97 and the base element 50 form a single unit. The reinforcing element 97 has a height 98 equal to the height 102 of the reinforcing structure 100. The reinforcing element 97 consists of individual ridges extending parallel to the longitudinal direction 3 within the edge region 58 of the base element 50. The leads 76 are separated from the reinforcing element 97 by an insulating layer 78.

[0173] In the embodiment shown in Figure 5, the lead 76 is characterized by a first metal layer 72 and a second metal layer 74, each made of a different material. In other embodiments, the lead 76 may comprise a single metal layer.

[0174] The micromechanical beam 1 includes a reading structure 90 within the bent section 30. The reading structure 90 is located within a reading area 96. The reading area 96 is located at the center of the micromechanical beam 1 along the width direction 4.

[0175] The base element 50 has an opening 94, which is a through-hole, in the center of the reading structure 90. The opening 94 has a width 95 parallel to the width direction 4. The width 95 is 0.5 times the height 51 of the base element 50. Generally, the width 95 of the opening 94 is between 0.25 times and 1 time the height 51 of the base element 50.

[0176] The base element 50 is provided with openings 38 on both sides of the reading structure 90. Each opening 38 consists of a longitudinal slot parallel to the longitudinal direction 3. Each opening 38 is positioned between the edge of the base element 50 that divides the base element 50 in the width direction 4 and the reading structure 90. The openings 38 extend across the entire reading area 96. Each opening 38 has a length 39 parallel to the longitudinal direction 3 and a width 32 parallel to the width direction 4. The width 32 of the opening 38 is 0.5 times the height 51 of the base element 50. Generally, the width 32 is between 0.25 and 1 times the height 51 of the base element 50.

[0177] The base element 50 has notches 34 on both sides in the lateral direction along the width direction 4 of the base element 50. Due to the notches 34, the width 11 of the base element 50 narrows from a maximum width 36 to a minimum width 35 within the bending region 32. The minimum width 35 is 0.7 times the maximum width 36. In general, the minimum width 35 is between 0.4 and 0.9 times the maximum width 36, for example, between 0.6 and 0.8 times.

[0178] The length of the notch 34 at the lateral position corresponding to the maximum width 36 is equal to the length 31 of the bent portion 30. The base element 50 narrows to a minimum width 35 in the notch 34 and has a minimum width 35 over a length 37 in the notch 34. Thus, the length 37 is at least equal to the length 92 of the reading structure 19 parallel to the longitudinal direction 3.

[0179] Figure 6 shows a perspective view of another embodiment of the micromechanical beam 1 according to this disclosure. Unless otherwise specified, the embodiments shown in Figure 6 have the same configuration as the embodiments shown in Figures 3 to 5, and vice versa. The reinforcing structure 100 of the micromechanical beam 1 shown in Figures 3 to 5 has six protrusions 110, whereas the reinforcing structure 100 of the micromechanical beam 1 shown in Figure 6 has ten protrusions 110.

[0180] As shown in Figure 6, the support structure 201 is provided on the surface of the base element 50 facing the surface 52 on which the reinforcing structure 100 and the probe structure 7 are mounted.

[0181] In the micromechanical beam 1 shown in Figure 6, the length 10 is 165 μm, the maximum width 36 is 135 μm, the minimum width 35 is 115 μm, and the base element height 51 is 1.13 μm. The height of the probe structure is 6.6 μm. The effective mass density of micromechanical beam 1 is 2920 kg / m³. 3 Therefore, the effective Young's modulus is E = 150 GPa. As a result, the resonant frequency is 188.1 kHz and the spring constant is k = 1.2 N / m.

[0182] The width 112 of the ridge 110 is 2 μm, and the width 122 of the gap 120 is 3 μm. Furthermore, the height 102 of the ridge 110 is 4 μm. The lateral width 99 of the lead 76 is 6.5 μm. Furthermore, the width 95 of the central opening 94 within the reading structure 90 is 7 μm, and the width 32 of the longitudinal opening 38 is 4 μm.

[0183] In another embodiment, in the micromechanical beam 1 shown in Figure 6, the length 10 is 350 μm, the maximum width 36 is 185 μm, the minimum width 35 is 140 μm, and the height 51 of the base element is 1.34 μm. The height of the probe structure is 6.8 μm. The effective mass density of the micromechanical beam 1 is 2920 kg / m³. 3 Therefore, the effective Young's modulus is E = 150 GPa. As a result, the resonant frequency is 69.12 kHz and the spring constant is k = 2.29 N / m.

[0184] The width 112 of the ridge 110 is 5.2 μm, and the width 122 of the gap 120 is 4.8 μm. Furthermore, the height 102 of the ridge 110 is 4.5 μm. The lateral width 99 of the lead 76 is 9.9 μm. Furthermore, the width 95 of the central opening 94 within the reading structure 90 is 6 μm, and the width 32 of the longitudinal opening 38 is 5.2 μm.

[0185] In another embodiment, the micromechanical beam 1 comprises a reinforcing structure 100 having a height 102 of 3 μm and a base element 50 having a height 51 of 3 μm. In this case, the micromechanical beam 1 has a resonant frequency of 1800 kHz and a mechanical bandwidth of 6.4 kHz.

[0186] Figure 7 shows a cross-sectional view of an embodiment of the micromechanical beam 1 with nine ridges 110. Unless otherwise indicated, the embodiment shown in Figure 7 has the same configuration as the embodiments shown in Figures 3 to 5, and vice versa.

[0187] The second moment of area I of the cross-sectional view shown in Figure 6 r It can be expressed by the following equation.

number

[0188] Figures 8 and 9 illustrate the effect of the reinforcing structure 100 on the stress applied to the bent portion 30 of the micromechanical beam 1 according to this disclosure. Figure 8 shows the bending of the micromechanical beam 1 when it is deflected by a distance z in the height direction 5 in a configuration without the reinforcing structure 100, and Figure 9 shows the bending of the micromechanical beam 1 when it is deflected by a distance z in the height direction 5 in a configuration with the reinforcing structure (not shown in Figure 9). The amount and distribution of stress applied to the micromechanical beam 1 are indicated by the shading of the micromechanical beam 1. Compared to the micromechanical beam 1 shown in Figure 8, the stress applied to the bent portion 30 of the micromechanical beam 1 shown in Figure 9 increases by at least 18 times, but at a position further away from the bent portion 30 towards the free end 22 of the micromechanical beam 1, the stress decreases by at least an order of magnitude.

[0189] Figure 10 shows a detailed top view of the reading area 96 including the reading structure 90. The reading structure 90 consists of a Wheatstone bridge. It comprises a first contact 171 and a second contact 172, the second contact 172 being located on the opposite side of the opening 94 in the micromechanical beam 1 from the first contact 171. Thus, the first contact 171 and the second contact 172 are located on opposite sides of the rectangular opening 94.

[0190] The reading structure 90 further includes a third contact 173 and a fourth contact 174. The third contact 173 and the fourth contact 174 are located on the remaining opposing sides of the rectangular opening 94. The third contact 173 is electrically coupled between the first contact 171 and the second contact 172. The first resistor 175 connects the first contact 171 to the third contact 173, and the second resistor 176 connects the second contact 172 to the third contact 173. Furthermore, the fourth contact 174 is electrically coupled between the first contact 171 and the second contact 172, parallel to the third contact 173. Thus, the third resistor 177 connects the fourth contact 174 to the second contact 172, and the fourth resistor 178 connects the fourth contact 174 to the first contact 171.

[0191] Therefore, the second resistor 176 and the fourth resistor 178 are parallel to the longitudinal direction 3, and the first resistor 175 and the third resistor 177 are parallel to the width direction 4. The resistors 175, 176, 177, and 178 are composed of piezoresistive elements that have resistance that changes according to the stress applied to resistors 175, 176, 177, and 178.

[0192] The first contact 171 is grounded, and the second contact 172 is connected to a voltage line that connects to a voltage source that provides the operating voltage for the reading structure 90. The third contact 173 is connected to a first detection line that connects to a first input of a reading module that determines the resistance of the reading structure 90. The fourth contact 174 is connected to a second detection line that connects to a second input of the reading module.

[0193] As shown in Figure 10, the stress 180 indicated by the shading of the micromechanical beam 1 in Figure 10 is concentrated along the resistances 175, 176, 177, and 178 of the reading structure 90.

[0194] Figure 11 shows, for comparison, the stress 180 on the reading area 96 of a micromechanical beam 1 having a rectangular cross-section perpendicular to the longitudinal direction 3, and lacking a reinforcing structure 100, a notch 34 within the bent portion 30, and a portion tapering from a maximum width 36 to a minimum width 57. As shown in Figure 11, the stress 180 on the reading area 96 around the reading structure 90 is smaller than the stress 180 on the micromechanical beam 1 according to the present disclosure shown in Figure 10.

[0195] The sensitivity of the piezoresistive reading structure 90 is defined as the slope of the characteristic output curve dV / dz, which is defined as the change in output voltage dV for a given deflection dz due to a load force. It further represents the minimum input of beam deflection generated by a reference load that produces a measurable output voltage, or by the minimum load required to produce a measurable output voltage.

[0196] Figure 12 shows the differential output voltage 402 of the reading structure 90 as a function of the deflection 401 of the micromechanical beam 1 shown in Figure 11, and Figure 13 shows the differential output voltage 402 of the reading structure 90 as a function of the deflection 401 of the micromechanical beam 1 according to the present disclosure shown in Figure 10. As can be seen from these figures, the sensitivity or characteristic output curve of the micromechanical beam 1 according to the present disclosure is

number

number

[0197] The piezoresistor reading response time is defined as the time required for the differential output voltage measured on the detection line of the piezoresistor reading structure 90 to change from an initial value to a value within an acceptable range centered on the determined final voltage value.

[0198] Figure 14 shows the response of the output voltage 402 of the reading structure 90 to the instantaneous deflection 401 of the micromechanical beam 1 according to this disclosure, as a function of time 405. The micromechanical beam 1 is deflected by applying a stepped DC voltage to the lead 76 of the drive structure 70. Thus, the effective deflection of the micromechanical beam 1 in the height direction 5 is approximately 1200 nm, and the spring constant of the micromechanical beam is 2.85 N / m. As shown in Figure 14, the reading response time is less than 20 μs, and as a result, a bandwidth greater than 20 kHz is obtained. If the force applied to the micromechanical beam 1 when the vibration motion in the height direction 5 occurs is less than 10 nN, the reading structure 90 has a stepped response time of approximately 50 μs.

[0199] Figure 15 shows the first precursor structure 500 obtained when the method for fabricating the micromechanical beam 1 according to this disclosure is carried out.

[0200] The method includes providing a base structure having a base layer 501, an insulating layer 502, and a beam layer 503, wherein the insulating layer 502 is located above the base layer 501 in the height direction 5, and the beam layer 503 is located above the insulating layer 502 in the height direction 5. The base structure is composed of a silicon-on-insulator (SOI) wafer. The base layer 501 and the beam layer 503 are made of silicon, and the insulating layer 502 is composed of an oxide layer.

[0201] The base structure has a further insulating layer 505 on top of the beam layer 503. The further insulating layer 505 is composed of an oxide layer.

[0202] The insulating layer 502 is composed of an embedded oxide layer having a height of 300 nm in the height direction 5, and the beam layer 503 has a height of 15 μm. The back surface of the base layer 501, which faces away from the beam layer 503, is covered with 60 nm thick CVD silicon nitride. A further insulating layer 505 is composed of thermal SiO2 with a height of 300 nm.

[0203] The probe structure 7 is formed by a micromachining process. In this process, the probe mask 510 is coated onto an additional insulating layer 505, and the probe mask 510 is constructed by lithography. As a result, the first precursor structure shown in Figure 15 is obtained.

[0204] The probe mask 510 has a height of 1 μm.

[0205] Next, the probe structure 7 is defined by etching the beam layer 503, such as RIE etching and / or wet etching. This defines the probe structure 7 by an undercut formed beneath the probe mask 510 within the beam layer 503.

[0206] During the etching step, the probe mask pattern is transferred to the insulating layer 505 by wet etching, and in the subsequent step, the probe structure 7 is formed by wet etching in a hydrothermal solution of, for example, potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

[0207] After forming the probe structure 7, a protective layer 515 is formed on the beam layer 503 and the probe structure 7 to protect the probe structure 7 during subsequent processing. The protective layer acts as a passivation layer. The protective layer 15 is composed of an SiO2 / Si3N4 layer. The protective layer 515 has a height of 150 nm. It is composed of a zero-stress Si3N4 layer. The protective layer 515 is formed by plasma CVD and passivates the upper surface of the base structure.

[0208] As a result, the second precursor structure 520 shown in Figure 16 is obtained.

[0209] Figure 17 shows a third precursor structure 525 obtained by the method for fabricating the micromechanical beam 1 according to this disclosure.

[0210] The third precursor structure 525 is formed by applying a patterned photoresist to the upper surface of the protective layer 515 of the second precursor structure 520. Furthermore, electrical connections to the reading structure 90 are defined by injecting charge carriers into the beam layer 503. The protective layer 515 and the patterned photoresist are thus used as masks for carrier injection. Boron injection at 30 keV is performed here. Subsequently, the patterned photoresist is removed. This is done by microwave O2 plasma stripping, followed by annealing at 1050C for 30 minutes.

[0211] Furthermore, the method includes defining the resistances 175, 176, 177, and 178 of the reading structure 90. Exemplarily, these are defined by boron implantation at 20 keV in ultra-high vacuum, followed by rapid heating (RTA) at 1100°C for 30 seconds. Alternatively, the resistances 175, 176, 177, and 178 may be defined by implantation and annealing.

[0212] In subsequent lithography steps, the protective layer 515 contact holes are defined and etched to enable connection of the p+ diffusion region with metal paths. Plasma etching is performed for the etching process.

[0213] By performing the above steps of the method described above, the third precursor structure 525 shown in Figure 17 is obtained.

[0214] Figure 18 shows the fourth precursor structure 530 obtained by performing the method for fabricating the micromechanical beam 1.

[0215] The fourth precursor structure 530 is obtained by depositing a metal layer 532 on the protective layer 515 of the third precursor structure 525. The metal layer 532 is deposited by magnetron sputtering. The metal layer 532 has a height of 800 nm. The metal layer 532 is composed of an Al / Si / Mg thin film.

[0216] Furthermore, the method includes defining a drive structure 70 from the metal layer 532. The drive structure 70 is defined by lithography defining a photoresist followed by metal etching. The step of defining the drive structure 70 also includes defining a lead 76. The lead 76 is also defined by lithography followed by metal etching. Furthermore, the method includes defining a coupling that connects the micromechanical beam 1 to a control system by lithography followed by metal etching.

[0217] Subsequently, perform an annealing step in a 410°C N2 atmosphere for 50 minutes.

[0218] By implementing the above method, the fourth precursor structure 530 shown in Figure 18 is obtained.

[0219] Subsequently, a further protective layer is deposited. This further protective layer consists of a low-stress oxynitride layer, which is deposited by plasma-enhanced chemical vapor deposition (PECVD).

[0220] In a subsequent step, the reinforcing structure 100 is defined. The reinforcing structure 100 is defined by etching the beam layer 503. The mask for etching the reinforcing structure 100 is defined by a drive structure 70 which provides a patterned metal film that is a hard mask. In another embodiment of the method, the photoresist mask used to define the drive structure 70 may still be present when the step of defining the reinforcing structure 100 is being performed.

[0221] Alternatively, a separate mask for etching the reinforcing structure 100 may be formed by lithography. For example, the mask can be formed by patterned photoresist.

[0222] Dry etching is performed on the reinforcing structure 100. This involves removing the further protective layer in an FH3 / Ar mixed gas. Subsequently, silicon etching of the beam layer 503 is performed by a so-called gas chopping process. During etching, the beam layer 503 is thinned except in the area covered by the etch mask. The etch mask is also used to protect the probe structure 7 during etching.

[0223] As a result, the fifth precursor structure 535 shown in Figure 19 is obtained.

[0224] Subsequently, the base element 50 is defined by removing the base layer 501 from the region occupied by the self-supporting portion of the micromechanical beam 1. This includes the step of defining the self-supporting portion by performing lithography on the back surface of the base layer 501. Then, the base layer 501 is etched to produce a film having the self-supporting portion of the micromechanical beam 1. The pre-etching step is wet etching of CVD silicon nitride on the back surface of the base layer 501. Subsequently, the base layer 501 is etched with deep silicon anisotropic etching. The etching is performed in a hydrothermal solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH). The etching is stopped at an insulating layer 502 consisting of an embedded SOI oxide film (BOX). The lithography on the back surface of the base layer 501 is aligned with the front surface of the base layer 501 to obtain the desired beam design. The remainder of the base layer 501 located at the fixed end 20 of the micromechanical beam 1 forms the support structure 201.

[0225] As a result, the sixth precursor structure 536 shown in Figure 20 is obtained.

[0226] The method further includes defining the micromechanical beam 1, which includes a step of lithography on the upper surface followed by a dry etching step. The contour of the micromechanical beam 1 is defined in the subsequent lithography and dry etching steps. During etching, the BOX and oxide protecting the probe structure 7 are removed using HF vapor etching.

[0227] In the final step of microwave plasma stripping, the resist from the last lithography step is removed. This results in the sixth precursor structure 536 shown in Figure 21.

[0228] Subsequently, the micromechanical beam 1, including the support structure 201, is mechanically separated from the rest of the base layer 501.

[0229] In all embodiments, the micromechanical beam 1 can be part of an array of multiple micromechanical beams 1. In these embodiments, the array of multiple micromechanical beams 1 is fabricated in parallel and mechanically separated from the remaining silicon frame.

[0230] Figure 22 shows such an array consisting of four micromechanical beams 1 arranged adjacent to each other in the width direction 4. These micromechanical beams 1 are connected via a support structure 201.

[0231] In each micromechanical beam 1 shown in Figure 22, the length 10 is 91 μm, the maximum width 36 is 56 μm, the minimum width 35 is 41 μm, and the base element height 51 is 1.8 μm. The height of the probe structure is 5.6 μm. The effective mass density of micromechanical beam 1 is 2920 kg / m³. 3 Therefore, the effective Young's modulus is E = 150 GPa. As a result, the resonant frequency is 1.21 MHz and the spring constant is k = 1.24 N / m.

[0232] The width 112 of the ridge 110 is 2.3 μm, and the width 122 of the gap 120 is 2.1 μm. Furthermore, the height 102 of the ridge 110 is 3.7 μm. The lateral width 99 of the lead 76 is 5.6 μm. Furthermore, the width 95 of the central opening 94 within the reading structure 90 is 5.2 μm, and the width 32 of the longitudinal opening 38 is 3.2 μm.

[0233] Figure 23 shows another embodiment of the micromechanical beam 600 according to the present disclosure. Unless otherwise indicated, the micromechanical beam 600 has the same configuration as the disclosed micromechanical beam 1, and vice versa. The micromechanical beam 600 comprises a base element 50 having a straight edge along the longitudinal direction 3, and therefore does not have a portion that tapers from a maximum width 36 to a minimum width 57.

[0234] Figure 24 shows a cross-section perpendicular to the longitudinal direction 3 of an alternative embodiment of the micromechanical beam 1. Unless otherwise specified, the micromechanical beam 1 shown in Figure 24 has the same configuration as the disclosed micromechanical beam 1,600, and vice versa. In addition to the reinforcing structure 108 and the surface 52 of the base element 50, the micromechanical beam 1 includes a further reinforcing structure 150. Unless otherwise specified, the further reinforcing structure 150 has the same configuration as the disclosed reinforcing structure 100, and vice versa.

[0235] The further reinforcing structure 150 is located on a further surface 53 of the base element 50, and the further surface 53 is the surface opposite to the surface 52 in the height direction 5. The further reinforcing structure 150 is provided with a protrusion 110, which extends from the surface 53 in the opposite direction to the protrusion 110 of the reinforcing structure 100 that extends from the surface 52.

[0236] The further reinforcing structure 150 comprises two protrusions 110. These protrusions 110 are each located at the edge of the base element 50 in the width direction 4. Thus, these protrusions 110 extend parallel to the longitudinal direction 3. Similar to the protrusions 110 of the reinforcing structure 100, the protrusions 110 of the further reinforcing structure 150 are mounted on a metal layer 70 separated from the protrusions 110 by an insulating layer 78. The metal layer 70 and the insulating layer 78 have the same configuration as the corresponding layers 70, 78 installed on top of the protrusions 110 of the reinforcing structure 100.

[0237] Figure 25 shows a plan view of a further micromechanical beam 650 according to the present disclosure. Unless otherwise indicated, the micromechanical beam 650 has the same configuration as the disclosed micromechanical beam 1,600, and vice versa.

[0238] The further micromechanical beam 650 has a triangular shape. In this embodiment, the further micromechanical beam 650 is composed of an equilateral triangle. The baseline of the triangle is oriented parallel to the width direction 4 in the support structure 201. The probe structure 7 is located at the corner of the triangle opposite the baseline.

[0239] The further micromechanical beam 650 includes straight edges 54 extending from the bent section 30 to the probe section 25. Each straight edge 54 extends to the longitudinal position of the probe structure 7 in the longitudinal direction 3. Each straight edge 54 also extends to the longitudinal position of the reading structure 90 in the longitudinal direction 3. Thus, the straight edges 54 cover more than half of the reading area 96 along the longitudinal direction 3.

[0240] Each opening 38 is located within the bent portion 30 between the reading area 96 and the straight edge 54. Each opening 38 has a triangular shape. In this embodiment, each opening 38 is composed of a right triangle. Each hypotenuse of the triangle is oriented parallel to the straight edge 54. Further micromechanical beams 650 do not have notches 34 within the bent portion 30.

[0241] The further micromechanical beam 650 includes a reinforcing structure 100 having four protrusions 110. The joint at the longitudinal end 107 of the reinforcing structure 100 is curved. Therefore, the joint is an arc-shaped portion.

[0242] The longitudinal length 3 of the micromechanical beam 650 is 70 μm. The width of each resistor in the reading structure 90 is 4.5 μm, and the width of each ridge 110 is 5 μm. Each ridge 110 has a metal film made of aluminum.

[0243] In other embodiments, the micro - mechanical beam 650 does not include the reinforcement structure 100. In this case, illustratively, a meandering conductive structure connecting the leads 76 is provided between the probe part 25 and the base element 201. Similar to the embodiment featuring the reinforcement structure 100, this conductive structure may be composed of a heating element that excites the vibration of the micro - mechanical beam 650.

[0244] In all embodiments, the micro - mechanical beams 1,600,650 have a patterned multilayer structure, and the patterned multilayer structure includes the reinforcement structure 100. The patterned multilayer structure is patterned uniformly in the height direction (5). Each gap 120 between each ridge 110 of the reinforcement structure 100 is formed in a region excluding the multilayer structure.

[0245] In the micro - mechanical beam 1 shown in FIG. 4, the multilayer structure includes a metal structure 70 having a first metal layer 72, a second metal layer 74, an insulating layer 78, and a part of the substrate, and the part of the substrate is a substrate portion structured in the height direction (5) on the surface 52 of the base element 50.

[0246] In an alternative embodiment of the above - mentioned micro - mechanical beams 1,600,650, the reinforcement structure 100 also includes the insulating layer 78 and / or the metal structure 70. At least some of the dimensions and material properties of the reinforcement structure 100, such as the bending rigidity, the cross - section perpendicular to the longitudinal direction (3), the cross - sectional second moment of inertia about an axis parallel to the width direction (4), and the height 102, are given by the corresponding dimensions and material properties of the insulating layer 78 and / or the metal structure 70.

[0247] In a further alternative embodiment of the above - mentioned micro - mechanical beams 1,600,650, the reinforcement structure 100 is formed separately from the base element 50, and / or the surface 52 of the base element 50 carrying the reinforcement structure 100 is composed of a flat surface of the entire region of the reinforcement structure 100. The material of the base element 50 may not include the portion structured in the height direction (5).

[0248] For example, the reinforcing structure 100 does not have to include a portion made of the same material as the base element 50. The reinforcing structure 100 may consist only of layers made of a different material from the base element 50.

[0249] Figure 26 shows a cross-section perpendicular to the longitudinal direction 3 of a micromechanical beam 700, which is a further alternative embodiment of micromechanical beam 1. Unless otherwise specified, the micromechanical beam 700 shown in Figure 26 has the same configuration as the micromechanical beams 1,600 and 650 disclosed herein, and vice versa.

[0250] In the micromechanical beam 700, the reinforcing structure 100 is made of a different material from the base material of the base element 50.

[0251] The reinforcing structure 100 comprises a metal structure 70 and an insulating layer 78 provided between the metal structure 70 and the base element 50, that is, it consists of a metal structure 70 and an insulating layer 78. Unless otherwise specified, the metal structure 70 and the insulating layer 78 have the same configuration as the metal structure 70 and insulating layer 78 of the disclosed micromechanical beam 1, and vice versa. In other embodiments, the reinforcing structure 100 may comprise only the metal structure 70 and may not comprise the insulating layer 78. In this case, the insulating layer 78 can be a homogeneous layer in a plane perpendicular to the height direction 5.

[0252] The metal structure 70 comprises only a single metal layer. This metal layer consists of or contains tungsten, a tungsten alloy, molybdenum, a molybdenum alloy, or an aluminum-magnesium alloy. The insulating layer 78 consists of or contains SiO2.

[0253] In all embodiments, the height 75 of the metal structure 70 is 0.7 μm or more and 5 μm or less. The height 75 is at least 0.7 μm, at least 1 μm, at least 1.5 μm, at least 2 μm, at least 2.5 μm, at least 3 μm, at least 3.5 μm, at least 4 μm, or at least 4.5 μm. The height is 1 μm or less, 1.5 μm or less, 2 μm or less, 2.5 μm or less, 3 μm or less, 3.5 μm or less, 4 μm or less, 4.5 μm or less, or 5 μm or less. The width 112 of the ridge of the metal structure 70 is 0.7 μm or more and 2 μm or less. The width 112 is at least 0.7 μm, at least 0.8 μm, at least 1 μm, at least 1.25 μm, at least 1.5 μm, or at least 1.75 μm. Width 112 is 0.8 μm or less, 1 μm or less, 1.25 μm or less, 1.5 μm or less, 1.75 μm or less, or 2 μm or less.

[0254] In all embodiments, the height 73 of the insulating layer 78 is 0.7 μm or more and 2 μm or less. The height 73 is at least 0.7 μm, at least 0.8 μm, at least 1 μm, at least 1.25 μm, at least 1.5 μm, or at least 1.75 μm. The height 73 is 0.8 μm or less, 1 μm or less, 1.25 μm or less, 1.5 μm or less, 1.75 μm or less, or 2 μm or less. The width of the ridge of the insulating layer 78 is equal to the width 112 of the ridge of the metal structure 70.

[0255] The width 122 of each gap 120 between each ridge 110 of the metal structure 70 is 1 μm or more and 3 μm or less. For example, the width 122 is at least 1 μm, at least 1.25 μm, at least 1.5 μm, at least 1.55 μm, at least 2 μm, at least 2.25 μm, at least 2.5 μm, or at least 2.75 μm. The width 122 is 1.25 μm or less, 1.5 μm or less, 1.55 μm or less, 2 μm or less, 2.25 μm or less, 2.5 μm or less, 2.75 μm or less, or 3 μm or less.

[0256] Alternative metal structures 70 in other embodiments of the micromechanical beam 1,600,650 may consist of only a single metal layer.

[0257] All metal structures 70 having only a single metal layer may be composed of drive structures. In this case, the metal structure 70 may have a different coefficient of thermal expansion than the base element 50. This difference in the coefficient of thermal expansion between the single metal layer and the base element 50 induces bending of the micromechanical beam 1,600,650.

[0258] Exemplary, the micromechanical beam 700 includes a cover layer 80. The cover layer 80 covers the reinforcing structure 100. Furthermore, the cover layer 80 covers the entire reinforcing section 40. Even more exemplary, the cover layer 80 covers the entire micromechanical beam 700.

[0259] The cover layer 80 is made of silicon nitride. Exemplarily, it is made of Si3N4. The cover layer 80 is formed by atomic layer deposition.

[0260] The cover layer 80 has a thickness of 20 nm. Exemplarily, the thickness of the cover layer 80 is less than 10% of the thickness of the metal structure 70 (75) and / or the thickness of the reinforcing structure 100 (102), e.g., less than 5%, e.g., less than 3%.

[0261] The cover layer 80 forms a passivation layer.

[0262] All other embodiments of the micromechanical beam 1,600,650 relating to this disclosure may also include a cover layer 80.

[0263] The basic benchmarks of the micro - mechanical beam 1,600 according to the present disclosure are: (i) fundamental miniaturization scalability, (ii) regular atomic resolution, (iii) very easy to use, (iv) high - speed operation with wide bandwidth, and (v) excellent performance in any environment. In short, the micro - mechanical beam 1,600 is composed of active probes featuring a drive structure 70, and such active probes are promising for the development of future scanning probe technologies compared to passive probes of the optical readout type. Instead of moving a bulky sample stage, it is only necessary to move a more dynamic measurement head equipped with the micro - mechanical beam 1,600 over the sample. This fundamentally simplifies the AFM architecture and enables the re - placement of the AFM architecture in a space - saving manner.

Description of Signs

[0264] 1 Micro - mechanical beam 3 Longitudinal direction 4 Width direction 5 Height direction 7 Probe structure 10 Length 11 Width 12 Height 20 Fixed end 22 Free end 25 Probe part 30 Bending part 31 Length 32 Width 34 Notch 35 Minimum width 36 Maximum width 37 Length 38 Opening 39 Length 40 Reinforcement part 41 Length of the reinforcement part 49 Distance 50 Base element 51 Height ​​​​​​​​​ 58 Border region 70 Drive structure 72 1st metal layer 73. Height of the insulating layer 74 Second metal layer 75 Height of the drive structure 76 Reed 78 Insulating layer 79 Top side 80 Cover layer 90 Reading Structure 92 Longitudinal length 94 Aperture 96 Reading area 97 Reinforcement elements 98 Height 99 width 100 Reinforcement structure 101 Length 102 Height 104 width 107 Longitudinal end 108 1st end 109 2nd end 110 Prominence 111 Height 112 width 120 Gap 122 width 150 Further reinforcement structure 171 First contact point 172 Second contact point 173 Third contact point 174 Fourth contact point 175 1st resistance 176 2nd resistor 177 3rd resistor 178 4th resistor 180 stress 200 micromechanical beams 201 Support structure 401 Flexing 402 Output voltage 405 hours 500 First precursor structure 501 Base Layer 502 Insulating layer 503 Beam layer 505 Further insulating layer 510 Probe Mask 515 Protective layer 520 Second precursor structure 525 Third precursor structure 530 Fourth precursor structure 532 Metal layer 535 The fifth precursor structure 536 Sixth Precursor Structure 537 Precursor Structure VII 600 micromechanical beams 650 Micromechanical Beam 700 micromechanical beams< / z> < / z> < / z>

Claims

1. A micromechanical beam (1,600,650,700) for scanning probe measurement, lithography, etc., wherein the micromechanical beam (1,600,650,700) extends longitudinally (3) between a fixed end (20) and a free end (22). The beam (1,600,650,700) has a height (12) along the height direction (5) perpendicular to the longitudinal direction (3), and the height (12) is smaller than the width (11) along the width direction (4). The beam (1,600, 650, 700) has a bent portion (30) provided at the fixed end (20) in the longitudinal direction (3) of the beam (1,600, 650, 700), The beam (1,600, 650, 700) has a reinforcing portion (40) provided between the bent portion (30) and the free end (22) in the longitudinal direction (3), The beam (1,600,650,700) has a base element (50) and a reinforcing structure (100) provided on the base element (50) within the reinforcing portion (40). The reinforcing structure (100) is configured to increase the bending rigidity of the beam (1,600, 650, 700) within the reinforcing portion (40) with respect to bending in the height direction (5), and is a micromechanical beam (1,600, 650, 700).

2. The micromechanical beam (1,600,650,700) according to claim 1, wherein in the reinforcing portion (40), the bending stiffness of the base element (50) with the reinforcing structure (100) is, for example, at least 1.2 times, 2.5 times, 5 times, 8 times, 10 times, 15 times, or 20 times greater than the bending stiffness of the base element (50) without the reinforcing structure (100).

3. The micromechanical beam (1,600,650,700) according to claim 1 or 2, wherein the second moment of area of ​​the cross-sections of the base element (50) and the reinforcing structure (100) in a plane perpendicular to the longitudinal direction (3) with respect to bending around an axis parallel to the width direction (4) is, for example, at least 5 times, at least 10 times, at least 12 times, or at least 13 times the magnitude of the second moment of area of ​​a rectangle having the same width as the base element (50) and having the same area as the cross-sections of the base element (50) and the reinforcing structure (100) in the plane perpendicular to the longitudinal direction (3),

4. The micromechanical beam (1,600,650,700) according to any one of claims 1 to 3, wherein the height (102) of the reinforcing structure (100) in the height direction (5) is at least 0.1 times, for example, at least 0.2 times, at least 0.25 times, at least 0.5 times, or at least 1 time, of the height (51) of the base element (50) in the height direction (5).

5. The micromechanical beam (1,600,650,700) according to any one of claims 1 to 4, wherein the reinforcing structure (100) comprises at least one ridge (110) extending parallel to the longitudinal direction (3).

6. The aspect ratio of the height (102) of the ridge (110) in the height direction (5) to the width (113) of the ridge (110) in the width direction (4) is at least 0.1, for example, at least 0.2, or at least 0.

25. For example, the aspect ratio is at least 0.5, at least 1, at least 2.5, at least 3, or at least 3.

5. For example, the micromechanical beam (1,600,650,700) according to claim 5, wherein the aspect ratio is greater than 2.

5.

7. The micromechanical beam (1,600,650,700) according to claim 5 or 6, wherein the ridge (110) forms part of the conductive structure or forms a support for the conductive structure.

8. The reinforcing structure (100) comprises a plurality of ridges (110) extending parallel to the longitudinal direction (3) and arranged adjacent to each other along the width direction (4), according to any one of claims 5 to 7, for the micromechanical beam (1,600, 650, 700).

9. The micromechanical beam (1,600,650,700) according to claim 8, wherein the ridges (110) have the same width (102) in the width direction (4) and / or the same height (102) in the height direction (5).

10. The micromechanical beam (1,600,650,700) according to claim 8 or 9, wherein adjacent ridges (110) of the reinforcing structure (100) are connected at their staggered longitudinal ends (107) to form a meandering structure.

11. The reinforcing structure (100) is a continuous structure that extends continuously from the first end (108) to the second end (109) in a plane perpendicular to the height direction (5). For example, the first end (108) and / or the second end (109) are located at one end of the reinforcing portion (40) facing the fixed end (20) of the micromechanical beam (1,600, 650, 700), For example, the micromechanical beam (1,600,650,700) according to any one of claims 1 to 10, wherein the first end (108) and the second end (109) are located at the same end of the reinforcing portion (40).

12. The reinforcing structure (100) forms a part of the conductive structure (70), or forms a support for the conductive structure (70). For example, the micromechanical beam (1,600,650,700) according to any one of claims 1 to 11, wherein the conductive structure (70) provides a continuous conductive path for energization.

13. It has a patterned multilayer structure, The patterned multilayer structure has the reinforcing structure (100), For example, the patterned multilayer structure is uniformly patterned in the height direction (5), as described in any one of claims 1 to 12, for the micromechanical beam (1,600, 650, 700).

14. The micromechanical beam (1,600, 650, 700) according to any one of claims 1 to 13, wherein the reinforcing structure (100) and the base element (50) are made of the same material and are integrally joined together.

15. The reinforcing structure (100) includes a material different from the base material of the base element (50), For example, the micromechanical beam (1,600,650,700) according to any one of claims 1 to 13, wherein the reinforcing structure (100) is made only of a material different from the substrate of the base element (50).

16. The micromechanical beam (1,600,650,700) is provided with a conductive metal structure (70) electrically separated from the reinforcing structure (100) on the reinforcing structure (100), or The reinforcing structure (100) comprises the conductive metal structure (70), for example, the micromechanical beam (1,600,650,700) according to any one of claims 1 to 15.

17. The micromechanical beam (1,600,650,700) according to claim 16, wherein the metal structure (70) comprises two leads (76) for power connection that extend longitudinally through the bent portion (30).

18. The micromechanical beam (1,600,650,700) according to claim 16 or 17, wherein the metal structure (70) is stacked in the height direction (5) and has at least two conductive layers (72,74) configured to cause bending strain in the beam (1,600,650).

19. The micromechanical beam (1,600,650,700) according to any one of claims 16 to 18, wherein the reinforcing structure (100) is formed by etching the base element (50) using the metal structure (70) as an etch mask.

20. The beams (1,600, 650, 700) are provided within the reinforcing portion (40) and have a further reinforcing structure (150) positioned on a further surface (53) of the base element (50) of the beams (1,600, 650, 700). The micromechanical beam (1,600,650,700) according to any one of claims 1 to 19, wherein the surface (52) and the further surface (53) are parallel to each other and located on opposite sides of the base element (50) in the height direction (5).

21. The beam (1,600,650,700) has a reading structure (90) for measuring the mechanical vibration of the beam (1,600,650,700) in the height direction (5), and the reading structure (90) is, for example, a piezoresistive reading structure (90) and / or a Wheatstone bridge. The reading structure (90) is provided on the bent portion (30) of the beam (1,600,650,700), according to any one of claims 1 to 20, for the micromechanical beam (1,600,650,700).

22. The micromechanical beam (1,600,650,700) according to any one of claims 1 to 21, wherein the beam (1,600,650,700) has at least one transverse notch (34) within the bent portion (30).

23. The beams (1,600, 650, 700) have two transverse notches (34) on the sides of the beams (1,600, 650, 700) that face each other in the width direction (4) at the bent portion (30). The micromechanical beam (1,600,650,700) according to claim 22, wherein the width of the beam (1,600,650,700) is narrowed to 0.85 times or less the maximum width (36) of the beam (1,600,650,700) within the bent portion (30), for example, 0.8 times or less, 0.75 times or less, 0.7 times or less, or 0.67 times or less.

24. The micromechanical beam (1,600,650,700) according to claim 21 or 23, wherein the width of the beam (1,600,650,700) in the notch (34) is shifted by less than 20%, for example less than 10%, less than 5%, or less than 1%, from the minimum width (35) over a longitudinal length (37) at least equal to the longitudinal length (92) of the reading structure (90).

25. The beam (1,600, 650, 700) is equipped with a drive structure (70) configured to excite the mechanical vibration of the beam (1,600, 650, 700) in the height direction (5), The drive structure (70) is provided on the reinforcing portion (40), as described in any one of claims 1 to 24 (micromechanical beam (1,600, 650, 700).

26. The micromechanical beam (1,600,650,700) according to claim 25, wherein the reinforcing structure (100) is formed from a material different from the material of the drive structure (70).

27. The micromechanical beam (1,600,650,700) according to any one of claims 1 to 26, wherein the beam (1,600,650,700) has at least one longitudinal slot (38) extending over the length (31) of the bent portion (30).

28. In the reinforcing portion (40), the beam (1,600,650,700) tapers in the width direction (4) along the longitudinal direction (3) by at least 0.1 times, for example, at least 0.2 times, or at least 0.25 times, according to any one of claims 1 to 27, the micromechanical beam (1,600,650,700).

29. A method (200) for producing a micromechanical beam (1,600, 650, 700) according to any one of claims 1 to 28, wherein the method (200) is: - To provide a base material for the beam (1,600, 650, 700) (205), - A reinforcing structure (100) is created (210) on the surface (52) of the substrate perpendicular to the height direction (5), - Including the preparation of self-supporting beams (1,600, 650, 700) from the substrate (220), The beams (1,600,650,700) extend longitudinally (3) between a fixed end (20) and a free end (22). The beam (1,600,650,700) has a height (12) along the height direction (5) perpendicular to the longitudinal direction (3), and the height (12) is smaller than the width (11) along the width direction (4). The beam (1,600,650,700) has a bent portion (30) provided at the fixed end (20) in the longitudinal direction (3) of the beam (1,600,650,700), and a reinforcing portion (40) provided between the bent portion (30) in the longitudinal direction (3) and the free end (22). The reinforcing structure (100) is provided within the reinforcing portion (40), Method (200), wherein the reinforcing structure (100) is configured to increase the bending rigidity of the beams (1,600, 650, 700) within the reinforcing portion (40) with respect to bending in the height direction (5).

30. The process of manufacturing the aforementioned reinforcing structure (100) (210) is as follows: - To provide a metal structure (70) having leads (76) for power connection on the surface (52) of the substrate (212), - The method according to claim 29 (200), comprising etching the substrate parallel to the height direction (5) using the metal structure (70) as an etching mask (214).

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