Micromechanical beam

Abstract

The invention discloses a micromechanical beam for scanning probe measurements, lithography and the like. The micromechanical beam extends in a longitudinal direction between a fixed end and a free end. The beam has a height in a height direction perpendicular to the longitudinal direction, the height being smaller than a width in a width direction. Furthermore, the beam has a bending section, which is positioned at the fixed end of the beam in the longitudinal direction, and a reinforcing section, which is positioned between the bending section and the free end in the longitudinal direction. In the reinforcing section, the beam has a base element and a reinforcing structure positioned on the base element, where the reinforcing structure is configured to increase a flexural rigidity of the beam in the reinforcing section for bending in the height direction.

Description

Technical Field

[0001] The present disclosure relates to a micromechanical beam for use in scanning probe measurement, lithography, etc. and a method for manufacturing such a beam. Background Art

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

[0003] Active beam-based AFMs can achieve resolutions down to the atomic level. Recent advances in high-resolution AFMs have been performed on a variety of surfaces in air, liquid, or vacuum using piezoelectric scanners and active beams fabricated as microelectromechanical systems (MEMS). MEMS-based force sensing (or probe-based instruments) provides high-quality imaging at high imaging rates by using a sharp tip positioned at the end of the beam and characterizing the surface structure of the sample using a low force load or low tracking force. In photolithography mode, the tip is modified to imprint information onto the sample surface by, for example, field-emission electrons.

[0004] In the case of scanning probe microscopy (SPM), a probe is employed to detect probe-surface interactions and characterize different interactions with the sample down to the atomic size. The measured interaction forces are then correlated with the material properties of the surface and used to characterize interfaces, such as solid-liquid interfaces.

[0005] Micromechanical beams can also be used in parallel for high-throughput probe topology measurements, lithography, electrical measurements, or a variety of mass, fluid, viscosity detection, etc.

[0006] In order to achieve high-speed measurements and minimize wear on the tip positioned at the micromechanical beam, a non-contact mode of operation is often used. In non-contact mode, the van der Waals forces between the tip and the sample are detected by driving the micromechanical beam to oscillate at its resonant frequency and positioning the micromechanical beam close to the probe surface. Typical beam oscillation amplitudes are in the range of less than 1 nm. To control the beam oscillations, locking techniques are often applied. To achieve high imaging performance, the locking bandwidth must be much higher than the mechanical bandwidth of the beam. The scanning speed in non-contact mode is usually limited by the time required for the oscillating micromechanical beam to adapt to changes in the surface topology as the probe tip moves over the surface.

[0007] Typically, when the tip approaches or touches the surface, the bending of the beam is detected by reflecting a laser beam from the micromechanical beam and measuring the laser beam direction using a spectroscopic photodetector. The bending of the micromechanical beam then reveals the tip-sample interaction force. This method for probe measurement is called optical readout or optical beam deflection (OBD) readout. Although optical readout is the most common method for detecting the deflection of the beam, it is limited by diffraction at the micromechanical beam, which prevents conventional scanning probes from being scaled down to single μm.

[0008] Therefore, there is a need to provide a scanning beam design and a method for manufacturing such a beam that enables high speed scanning of surfaces and thereby obtains high quality, high resolution measurements. Summary of the Invention

[0009] The present disclosure provides a micromechanical beam for use in scanning probe measurement, photolithography, and the like, wherein the micromechanical beam extends in a longitudinal direction between a fixed end and a free end. The beam has a height along a height direction perpendicular to the longitudinal direction, the height being less than the width along a width direction. Furthermore, the beam has a bending section and a reinforcement section, the bending section being positioned at the fixed end of the beam in the longitudinal direction, and the reinforcement section being positioned between the bending section and the free end in the longitudinal direction. In the reinforcement section, the beam has a base member and a reinforcement structure positioned on the base member, wherein the reinforcement structure is configured to increase the bending stiffness of the beam in the reinforcement section when bending in the height direction.

[0010] This disclosure is based on the recognition that the mechanical bandwidth of a beam at its resonant frequency limits the measurement speed and achievable resolution during scanning operations. Beams with higher mechanical bandwidths respond more quickly to topographic differences than beams with lower mechanical bandwidths and are more suitable for high-speed measurements. Consequently, high mechanical bandwidths enable high sensing and scanning speeds.

[0011] In addition to external effects such as the damping of the beam by the surrounding medium and the stiffness of the sample at the location the beam is scanning, the mechanical bandwidth of the beam is also determined by the spring constant and effective mass of the beam. Therefore, the bandwidth increases as the effective mass decreases. Therefore, reducing the effective mass of the beam allows for an increase in bandwidth and, therefore, also allows for higher scanning speeds. The ratio of the spring constant to the effective mass is also proportional to the resonant frequency of the beam, whereby a higher resonant frequency allows for faster scanning speeds. The reinforcement structure according to the present disclosure then serves to increase the stiffness to mass ratio of the beam and, at the same time, allows for a reduction in the mass of the beam while keeping the stiffness constant.

[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 oscillatory motion. The damping of a beam can be characterized by a dimensionless parameter, Q, also known as the quality factor or Q factor. It describes the rate of energy transformation in the system and is proportional to the ratio between the energy stored in the system and the energy lost during the oscillation period. The quality factor, Q, is usually defined as the resonant frequency divided by the resonant width at half the maximum energy, i.e., Q = f res / Δf. When the mass of the beam is reduced, for example by reducing the size of the beam and / or by using lighter materials for the beam, the mechanical bandwidth of the beam (defined as f res The reduction in effective mass achieved by the reinforcement structure can be equivalent to reducing the Q factor by at least an order of magnitude, resulting in a significant increase in the mechanical bandwidth of the beam.

[0013] Because the reinforcement section, and therefore the reinforcement structure, is positioned between the free and fixed ends of the beam, bending of the beam primarily occurs within the curved section at the fixed end of the beam, while bending of the remaining independent portions of the beam is suppressed. This concentration of bending within the curved section increases stress within the curved section, making the curved section particularly suitable for accommodating readout structures, such as piezoresistive readout structures, that are susceptible to localized stress in the beam.

[0014] Without a reinforcement structure, the stresses generated by beam bending would be distributed along the entire length of the beam. However, the reinforcement section only allows the beam to bend between the fixed end and the beginning of the reinforcement section, and the reinforcement section itself is effectively non-deformable. The stresses in the bending region of a beam with a reinforcement structure can be at least 9 times higher, such as at least 12 times, at least 15 times, or at least 18 times higher, than in a beam without a reinforcement structure. For example, the stresses in a beam with a reinforcement structure can be 18.7 times higher than in a beam without a reinforcement structure.

[0015] Compared to a beam without reinforcement, the reinforcement structure allows, on the one hand, to reduce the beam's mass while maintaining a constant stiffness, or, on the other hand, to increase its stiffness while maintaining a constant mass. Furthermore, the reinforcement structure serves to concentrate stresses in the bending section of the beam. This improves the sensitivity of stress-based measurement schemes (such as piezoresistive readouts) performed in the bending region.

[0016] In summary, providing a stiffening structure within the stiffened section of the beam allows for high scan rates and sensitive readout of the beam oscillations.

[0017] The beam may include a probe structure positioned at its free end. The probe structure may be configured to interact with a sample surface positioned proximate the beam. The probe structure may be configured, for example, as a sharp tip, a cylinder, etc. The probe structure may include a crystalline material. For example, the probe structure may include the material of the beam. The probe structure may also include or be composed of a material different from the material of the beam. For example, the probe structure may also include soft materials and / or biological materials, such as molecules. The probe structure may also include hard materials, such as gallium nitride diamond.

[0018] The longitudinal direction, width direction, and height direction are orthogonal to each other. The length of the beam in the longitudinal direction can be greater than the height of the beam and / or the width of the beam. The beam can be configured as a plate, wherein the height is less than the length and width, for example, at least 1 / 10, 1 / 25, 1 / 50, or 1 / 100.

[0019] The beam is typically configured to oscillate in the height direction. The resonant frequency of the first bending mode of the beam in the height direction may be at least 30 kHz, such as at least 40 kHz, 50 kHz, 55 kHz, or 60 kHz. Additionally or alternatively, the resonant frequency of the first bending mode may be at most 10 MHz, such as at most 5 MHz, at most 2 MHz, at most 500 kHz, 400 kHz, 300 kHz, 275 kHz, or 250 kHz.

[0020] The fixed ends of the beams can be clamped to a support structure. The support structure has a greater height than the beams. The beams and the support structure can be made of the same material. For example, the beams can be integrally formed with the support structure. Alternatively, the support structure can be separated from the beams by an intermediate layer. For example, the support structure and the beams can be made of silicon, and the intermediate layer can be configured as a silicon oxide layer.

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

[0022] The beam may comprise a base material, such as silicon or diamond. The base element within the reinforcement section may comprise, for example, consist of, a base material. The probe structure may also comprise, for example, consist of, a base material. Furthermore, the support structure may also comprise, for example, consist of, a base material.

[0023] The beam may further include a base member within the curved section. The base member of the curved section may be made of a base material. The height of the base member of the curved section may be equal to the height of the base member of the reinforcing section. The base member of the curved section may be integrally formed with the base member of the reinforcing section.

[0024] The length of the beam in the longitudinal direction may be at least 20 μm, such as at least 30 μm or at least 40 μm. The length of the beam may be at most 500 μm, such as at most 450 μm, at most 400 μm, or at most 350 μm. For example, the length may be between 150 μm and 400 μm. The length may be between 150 μm and 170 μm, such as 165 μm, or between 325 μm and 375 μm, such as 350 μm.

[0025] The length of the reinforcement structure in the longitudinal direction may be at least 0.25 times the length of the beam in the longitudinal direction, such as at least 0.3 times, at least 0.4 times, at least 0.45 times, or at least 0.5 times. The length of the reinforcement structure in the longitudinal direction may be at most 0.75 times the length of the beam in the longitudinal direction, such as at most 0.7 times, at most 0.6 times, at most 0.55 times, or at most 0.5 times. A reinforcement structure of such length provides, on the one hand, a structural increase in the stiffness of the beam, and, on the other hand, allows the integration of additional structures along the longitudinal extent of the beam.

[0026] The length of the reinforcement structure may be between 10 μm and 300 μm, such as between 15 μm and 200 μm or between 15 μm and 60 μm. For example, the length of the reinforcement structure may be between 50 μm and 250 μm. The length of the reinforcement structure may be between 40 μm and 360 μm, such as between 75 μm and 270 μm or between 80 μm and 200 μm. The length of the reinforcement structure may be between 40 μm and 160 μm, such as between 75 μm and 100 μm or between 80 μm and 95 μm. The length of the reinforcement structure may also be between 90 μm and 360 μm, such as between 135 μm and 270 μm or between 160 μm and 200 μm.

[0027] The width of the reinforcement structure in the width direction may be at least 0.2 times, such as 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, of the minimum width of the base element in the reinforcement section. The width of the reinforcement structure may be at least 0.2 times, such as 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, of the maximum width of the base element in the reinforcement section. For example, the width of the reinforcement structure can be between 0.8 and 0.95 times or between 0.85 and 0.9 times (such as 0.88 times) the minimum width of the base element in the reinforcement section, and / or can be between 0.5 and 0.7 times or between 0.55 and 0.65 times (such as 0.6 times) the maximum width of the base element in the reinforcement section.

[0028] The width of the reinforcement structure may be between 10 μm and 240 μm, such as between 15 μm and 150 μm or between 15 μm and 40 μm. The width of the reinforcement structure may be between 35 μm and 240 μm, such as between 50 μm and 180 μm or between 65 μm and 130 μm. The width of the reinforcement structure may be between 60 μm and 240 μm, such as between 90 μm and 180 μm or between 110 μm and 130 μm. The width of the reinforcement structure may also be between 35 μm and 140 μm, such as between 50 μm and 105 μm or between 65 μm and 75 μm.

[0029] The length of the curved section along the longitudinal direction may be at least 0.05 times, such as 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 beam along the longitudinal direction. The length of the curved section may be at most 0.4 times, such as at most 0.3 times, at most 0.2 times, at most 0.15 times, or at most 0.11 times, the length of the beam along the longitudinal direction. Bending a section of such length provides sufficient flexibility on the one hand, and on the other hand, concentrates the stresses generated by the bending in the area adapted for efficient readout.

[0030] The length of the curved segment may be between 2.5 μm and 80 μm, such as between 2.5 μm and 30 μm. For example, the length of the curved segment may be between 5 μm and 15 μm. The length of the curved segment may be between 10 μm and 80 μm, such as between 15 μm and 60 μm or between 18 μm and 45 μm. The length of the curved segment may be between 20 μm and 80 μm, such as between 30 μm and 60 μm or between 35 μm and 45 μm. The length of the curved segment may also be between 10 μm and 40 μm, such as between 15 μm and 30 μm or between 18 μm and 25 μm.

[0031] According to an embodiment, the reinforcement structure is positioned at a surface of the base element which is substantially perpendicular to the height direction. This may provide a more efficient reinforcement of the beam in the reinforcement section compared to other surfaces.

[0032] According to an embodiment, the reinforcement structure and the probe structure are positioned at the same surface of the base element. This allows both the reinforcement structure and the probe structure to be manufactured from the same side of the base element and thus facilitates the production of the micromechanical beam.

[0033] According to an embodiment, the reinforcement structure protrudes from the base element as an independent structure.Such an independent structure provides efficient reinforcement.

[0034] According to an embodiment, the beam includes a passivation layer positioned on a surface of the beam. Thus, the reinforcement structure includes, for example, consists of, the same material as the passivation layer. For example, the reinforcement structure can be formed by structuring the passivation layer. The material of the passivation layer can be, for example, silicon nitride or Si3N4 and / or silicon oxide or SiO2.

[0035] According to an embodiment, in the reinforced section and for bending in the height direction, the bending stiffness of the base element with the reinforcement structure is at least, for example, 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 without the reinforcement structure. This increase in stiffness allows for a significant reduction in the mass of the beam and, therefore, also a significant increase in the bandwidth. The bending stiffness of the base element without the reinforcement structure may be the bending stiffness of the base element within the reinforced section.

[0036] According to an embodiment, the bending stiffness of the beam for bending in the height direction is at least 1.1 times higher in the reinforced section than in the curved section, such as 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. This stiffness ratio of the reinforced section to the curved section effectively concentrates stress caused by oscillation of the beam in the curved section, which has a lower stiffness than the reinforced section.

[0037] According to an embodiment, the cross-section of the base member and the reinforcement structure in a plane perpendicular to the longitudinal direction has a second moment of section for bending about an axis parallel to the width direction that is greater than the second moment of section of a rectangle having the same width as the base member and the same area as the cross-section of the base member and the reinforcement structure in a plane perpendicular to the longitudinal direction, such as at least 5 times, at least 10 times, at least 12 times, or at least 13 times. Compared to a beam having a rectangular cross-section, the increase in the second moment of section of the beam according to the present disclosure allows the size and mass of the beam to be significantly reduced without reducing the stiffness (compared to a rectangular beam). Consequently, the smaller and lighter beam allows for an increase in bandwidth compared to a rectangular beam. The second moment of section can also be expressed as a moment of inertia or an area moment of inertia.

[0038] Alternatively or additionally, for bending about an axis parallel to the width direction, the second moment of section of the cross section of the base element and the reinforcement structure in a plane perpendicular to the longitudinal direction may be greater than the second moment of section of the cross section of the base element alone in the reinforcement section and in a plane perpendicular to the longitudinal direction, such as at least 1.05 times, at least 1.1 times, at least 1.15 times or at least 1.2 times.

[0039] According to an embodiment, for bending about an axis parallel to the width direction, the second moment of the cross section of the beam perpendicular to the longitudinal direction is greater in the reinforced section than in the bent section, such as at least 1.1 times greater, such as 1.15 times, 1.2 times, 1.25 times, 1.3 times, or 1.4 times greater. This effectively concentrates the stress that occurs when the beam oscillates about an axis parallel to the width direction within the bent section and facilitates stress-based reading of the oscillations within the bent section.

[0040] According to embodiments, the cross-section of the base element and the reinforcement structure in a plane perpendicular to the longitudinal direction can have an area that is, for example, at least 1.05 times, 1.08 times, or 1.1 times smaller than the area of a rectangle having the same width as the base element and the same second moment of cross-section as the cross-section of the base element and the reinforcement structure. This reduction in area results in a lower mass of the beam according to the present disclosure and, therefore, a greater bandwidth compared to a rectangular beam, and thus enables higher scanning speeds.

[0041] According to an embodiment, the height of the reinforcement structure in the height direction is equal to at least 0.1 times the height of the base element in the height direction, such as at least 0.2 times, at least 0.25 times, at least 0.5 times, or at least 1 times. A greater height of the reinforcement structure also increases the stiffness of the beam in the reinforcement section, which allows reducing the mass without simultaneously reducing the stiffness of the beam. The height of the reinforcement structure may be 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 reinforcement structure may be at most 1 times, 1.5 times, 2 times, 2.5 times or 5 times the height of the base element.

[0043] For example, the height of the reinforcement structure may be at most 2.5 μm, at most 3 μm, at most 3.5 μm, at most 4 μm, at most 5 μm, at most 6 μm, at most 10 μm, at most 15 μm, at most 20 μm or at most 40 μm.

[0044] The height of the reinforcement structure may be between 0.7 μm and 5 μm. The height may be 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 may be at most 1 μm, at most 1.5 μm, at most 2 μm, at most 2.5 μm, at most 3 μm, at most 3.5 μm, at most 4 μm, at most 4.5 μm, or at most 5 μm.

[0045] The Young's modulus of at least one material layer of the reinforcement structure or the reinforcement structure may be at least 100 GPa, such as 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 may be 411 GPa (for example, when the material layer is made of tungsten), or may be 330 GPa (for example, when the material layer is made of molybdenum). For example, the material layer may have a height that 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 reinforcement structure.

[0046] The Young's modulus of the at least one material layer of the reinforcement structure or the reinforcement structure may be at least 3.5 times, such as 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, of the Young's modulus of the base material of the base element. This provides for efficient reinforcement of the micromechanical beam within the reinforcement section.

[0047] According to an embodiment, the reinforcement structure comprises at least one ridge extending parallel to the longitudinal direction. The longitudinal ridge provides an effective measure for increasing the stiffness of the beam for bending perpendicular to the ridge. The ridge increases the viscosity of the beam's surface, which results in higher damping and a lower Q factor.

[0048] According to an 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, such as at least 0.2 or at least 0.25. Since the stiffness of the reinforcement structure increases with the increase of the aspect ratio of the ridge, the ridge with a high aspect ratio can provide efficient reinforcement of the beam. The height of the ridge can be equal to the height of the reinforcement structure.

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

[0050] The ratio of the width of the ridge to the height of the base element may be at least 0.4, at least 0.8, at least 1.5, at least 2.5, at least 3, or at least 4. Additionally or alternatively, the ratio of the width of the ridge to the height of the base element may be at most 4, at most 5, at most 8, at most 20, or at most 40. For example, the ratio of the width of the ridge to the height of the base element may be 4.

[0051] The ridges may have a width of 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. Additionally or alternatively, the ridges may have a width of at most 3 μm, at most 4 μm, at most 4.5 μm, at most 5 μm, at most 6 μm, or at most 10 μm. For example, the width of the ridges may be 4.5 μm.

[0052] The width of the ridge may be between 0.7 μm and 2 μm. The width may be 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 may be at most 0.8 μm, at most 1 μm, at most 1.25 μm, at most 1.5 μm, at most 1.75 μm, or at most 2 μm.

[0053] According to an embodiment, the reinforcement structure comprises a plurality of ridges, such as at least two ridges extending parallel to the longitudinal direction and placed next to each other in the width direction. This further increases the stiffness of the beam in the reinforcement section.

[0054] The ridges may have the same height and / or the same width. The spacing between the ridges, which is the width of the gap between the ridges, may be at least 0.1 times, at least 0.25 times, at least 0.5 times, at least 0.75 times, or at least 1 times the width of the ridge. Additionally or alternatively, the spacing may be at most 0.5 times, at most 0.75 times, at most 1 times, at most 1.5 times, or at most 2 times the width of the ridge.

[0055] The spacing or width of the gaps between the ridges may be 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. Additionally or alternatively, the gaps may have a width of at most 3 μm, at most 4 μm, at most 6 μm or at most 10 μm.

[0056] The gap may have a width of 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 gap may have a width of at most 1 μm, at most 1.25 μm, at most 1.5 μm, at most 1.75 μm, at most 2 μm, at most 2.25 μm, at most 2.5 μm, at most 2.75 μm, at most 3 μm, at most 3.25 μm, at most 3.5 μm, at most 3.75 μm, at most 4 μm, at most 4.25 μm, or at most 4.5 μm.

[0057] According to an embodiment, the ridges have the same width in the width direction and / or the same height in the height direction. This allows for simple and reliable manufacture of the ridges.

[0058] The reinforcing structure may comprise one ridge or a plurality of ridges. For example, the reinforcing structure may comprise at least 2, at least 4, at least 6, at least 10, at least 15, at least 20, at least 30, at least 50, at least 75, or at least 90 ridges. The reinforcing structure may comprise at most 2, at most 4, at most 6, at most 10, at most 15, at most 20, at most 30, at most 50, at most 75, at most 90, or at most 100 ridges.

[0059] According to an embodiment, adjacent ridges of the reinforcement structure are connected to each other at alternating longitudinal ends to form a meandering structure. This allows the ridges to be integrated into other functional structures of the micromechanical beam. For example, the ridges can form part of a conductive structure, or a support for such a conductive structure of the beam. Connecting the ends of the ridges then provides a continuous path for current to flow through the conductive structure.

[0060] The reinforcement structure may include an even number of connected ridges so that both ends of the meander structure are located at the same end of the beam, for example at a fixed end of the beam. This allows coupling the conductive structure associated with the reinforcement structure to an electrical energy source at the respective ends of the beam.

[0061] According to an embodiment, the reinforcing structure is a continuous structure extending continuously from the first end to the second end in a plane perpendicular to the height direction. Such a reinforcing structure can be configured as a zigzag structure, for example. The reinforcing structure can include a zigzag ridge extending continuously from the first end to the second end.

[0062] For example, the first end and / or the second end can be positioned at the end of the reinforcement section that faces the fixed end of the micromechanical beam. For example, the first end and the second end can be positioned at the same end of the reinforcement section, such as at the end of the reinforcement section that faces the fixed end of the micromechanical beam. This allows, for example, forming a conductive structure as part of the reinforcement structure or forming a conductive structure on top of the reinforcement structure.

[0063] According to an embodiment, the reinforcement structure forms part of the conductive structure or forms a support for the conductive structure.Thus, the conductive structure may provide a continuous path for the current flow.

[0064] According to an embodiment, the micromechanical beam comprises a patterned multilayer structure, wherein the patterned multilayer structure comprises a reinforcement structure. For example, the patterned multilayer structure can be patterned homogeneously in the height direction at least in the reinforcement section, for example, over the entire surface of the micromechanical beam and / or over the entire micromechanical beam. The multilayer structure can be placed on top of a substrate element, such as on top of a surface of the substrate element. The multilayer structure can have been patterned by etching, electroplating, laser cutting, electron beam machining (EBM), etc.

[0065] This multilayer structure allows different functional structures to be integrated into the reinforcement structure. For example, the multilayer structure can also provide a conductive structure and / or a driving structure.

[0066] The reinforcement structure can be made of a semiconductor, a conductor (such as a metal), or an insulator (such as a polymer such as acrylic or parylene). The reinforcement structure can be configured as a thin film, such as an acrylic or parylene film. For example, the reinforcement structure can be made of silicon, silicon oxide, silicon nitride, metal, or diamond.

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

[0068] According to an embodiment, the reinforcement structure and the base element are at least partially homogeneous in material and integrally connected. This provides a reliable connection between the base element and the reinforcement structure and further strengthens the beam within the reinforcement section. For example, the reinforcement structure may be at least partially formed by selectively removing material from portions of the base element. These portions may have been removed, for example, by etching, laser cutting, electron beam machining (EBM), or the like.

[0069] According to an embodiment, the reinforcement structure comprises a material different from the base material of the base element. For example, the reinforcement structure can be made entirely of a material different from the base material of the base element. The material different from the base material can be, for example, a metal.

[0070] According to an embodiment, the beam includes a conductive metal structure located on top of a reinforcement structure, the conductive metal structure being electrically isolated from the reinforcement structure. For example, such a metal structure can be used to heat the beam. Additionally or alternatively, the metal structure can also be configured as a thermomechanical actuator, such as a bimetallic actuator. The metal structure can be made of a different material than the reinforcement structure.

[0071] In other embodiments, the reinforcement structure may further include a conductive metal structure. For example, the reinforcement structure may consist of a conductive metal structure.

[0072] The metal structure may be electrically isolated from the reinforcement structure and / or the base element by an insulating protective layer, such as an oxide layer.

[0073] The conductive metal structure can be configured as at least part of a current loop. The conductive metal structure can form a continuous conductive structure extending from a first end to a second end. In the case of an embodiment including a reinforcement structure having only a single ridge, the first end can be positioned at one end of the reinforcement section in the longitudinal direction, and the second end can be positioned at the opposite end of the reinforcement section. At one of these ends, for example, at an end away from the fixed end of the micromechanical beam, the metal structure can be conductively connected to the base element of the micromechanical beam, and the current loop can be closed via the base element. Along the rest of the ridge, the metal structure can be electrically insulated from the base element.

[0074] In other embodiments, the reinforcement structure may include an even number of ridges that are placed next to each other in the width direction and connected to each other at alternating longitudinal ends. The conductive metal structure may then form a closed current loop along the ridges, whereby both ends of the conductive metal structure are located on the same side of the reinforcement section in the longitudinal direction, for example, on the side facing the fixed end of the micromechanical beam.

[0075] The closed current loop may form part of a drive structure to drive the mechanical oscillations of the beam.

[0076] The beam may include a reinforcing element within the curved section. The reinforcing element may be configured to prevent stress buildup at the reinforcing element, thereby concentrating stress generated by the bending of the beam in the readout region of the curved section. The reinforcing element may be positioned at the widthwise edge of the beam. The reinforcing element may be elongated in the longitudinal direction. For example, the reinforcing element may be configured as an elongated ridge. With respect to undisclosed differences, the reinforcing structure may be configured as disclosed for the reinforcing structure, or vice versa.

[0077] The reinforcing element may have a width that is greater than the width of the ridge of the reinforcing structure in the width direction. This enhances the reinforcing function of the reinforcing element compared to the reinforcing function of the ridge of the reinforcing structure.

[0078] The stiffening element may be separated from the readout region by an opening in the beam. The opening may extend parallel to the stiffening element. Such an opening further concentrates strains generated by bending of the beam within the readout region.

[0079] The width of the opening in the readout structure in the width direction may be at least 0.1 times, 0.25 times, 0.5 times, or 1 times the height of the base element in the curved section. Additionally or alternatively, the width of the opening may be at most 0.5 times, 1 times, 2 times, or 5 times the height of the base element in the curved section.

[0080] The width of the opening in the readout structure in the width direction may be at least 0.25 μm, at least 0.3 μm, at least 0.4 μm or at least 0.5 μm. Additionally or alternatively, the width may be at most 5 μm, at most 10 μm, at most 20 μm or at most 50 μm.

[0081] In other embodiments, the micromechanical beam may include only openings without reinforcing elements. For example, the openings may extend parallel to the longitudinal direction of the micromechanical beam. In addition to the openings, the micromechanical beam may also include additional openings located on the side of the beam opposite the openings.

[0082] In addition to the reinforcement element, the beam may also include an additional reinforcement element positioned within the curved section. With respect to undisclosed differences, the additional reinforcement element may be configured as disclosed for the reinforcement element, or vice versa. The two reinforcement elements may be positioned at opposing edges of the beam within the curved section. Additionally or alternatively, a readout region may be positioned between the two reinforcement elements. This effectively concentrates the strains generated by the bending of the beam within the readout region.

[0083] A micromechanical beam having one or more reinforcement elements can also be configured without reinforcement structures and / or reinforcement sections. Therefore, the present disclosure also relates to a mechanical beam having only at least one reinforcement element. All embodiments disclosed for a micromechanical beam having reinforcement sections also apply to a micromechanical beam having only reinforcement elements.

[0084] According to an embodiment of a beam comprising a conductive metal structure, the metal structure includes leads extending longitudinally through a curved section for connecting to a power source. The leads can be positioned on a reinforcement element within the curved section. For example, the reinforcement element and the additional reinforcement element can carry the leads. In other embodiments, the leads can also form the reinforcement element.

[0085] According to an embodiment, the leads are positioned in the edge region of the curved section. This concentrates the strain caused by the bending of the beam between the leads. The edge region may include two sub-regions positioned at opposite edges of the beam extending parallel or substantially parallel to the longitudinal direction. Each sub-region may include one of the leads. The two sub-regions may be positioned on opposite sides of the readout region in the width direction.

[0086] According to an embodiment, the width of the leads in the bend section is greater than the width of the ridge of the reinforcement structure. This reduces the resistance of the leads within the bend section and, therefore, also reduces the thermal impact of the leads on the beam within the bend section. Furthermore, the wider leads also increase the stiffness of the beam in the area occupied by the leads.

[0087] The lateral width of the lead may be 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 bend region. Additionally or alternatively, the lateral width of the lead may be at most 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 bend region.

[0088] For example, the lateral width of the lead may be equal to at least 0.25 μm, at least 0.3 μm, at least 0.4 μm or at least 0.5 μm. Additionally or alternatively, the lateral width may be equal to at most 2.5 μm, at most 5 μm, at most 10 μm or at most 15 μm.

[0089] According to an embodiment, a metal structure includes at least two conductive layers stacked one on top of the other in the height direction, forming a thermally active multi-metal structure that induces bending strain in a beam when heated. Thus, the metal structure can form an actuator for bending the beam in the height direction. For example, the metal structure can be configured to drive oscillations in the height direction of the beam. The conductive layers can be made of materials with different coefficients of thermal expansion. The metal structure can form a thermomechanical actuator.

[0090] In the case of other embodiments, the metal structure may also include 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 include or consist of aluminum, tungsten, a tungsten alloy, an aluminum-magnesium alloy, molybdenum, and a molybdenum alloy.

[0092] Tungsten and molybdenum are metallic materials that exhibit excellent resistance to heat and mechanical stress, high resistance to corrosion and wear, high melting points, mechanical strength at high temperatures, and high hardness at room temperature. The metal layer can be formed by dual-target or multi-target magnetron sputtering deposition.

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

[0094] Metal layers (such as tungsten or molybdenum polycrystalline layers and / or thin film layers) may have been structured by dry etching (e.g., by reactive ion etching), for example, in SF6 and SF6+N+CHF3 gas mixtures. The electron energy during etching may be at most 100 eV, 75 eV, or 50 eV, or less than 100 eV, 75 eV, or 50 eV. Such energy provides a small undercut at the edge of the metal layer.

[0095] The coefficient of thermal expansion of at least one metal layer (such as each metal layer) can differ from the coefficient of thermal expansion of the base material of the base layer by at most 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%. This matches the thermal expansion coefficients of the metal layer and the base material to prevent thermal stress from damaging the cantilever. In addition, the coefficient of thermal expansion of at least one metal layer (such as each metal layer) can differ from the coefficient of thermal expansion of the base material of the base layer by at least 2.5%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. This provides efficient actuation of bending of the micromechanical beam upon heating of the metal layer (such as upon resistive heating of the metal layer).

[0096] According to an embodiment, the reinforcement structure has been formed by etching the base element using the metal structure as an etching mask. This allows for a more cost-effective manufacture of the beam since it eliminates the need to define a separate etching mask for manufacturing the reinforcement structure.

[0097] According to an embodiment, the beam has another reinforcing structure positioned in the reinforcing section and placed on another surface of the beam's base member, wherein the other surface and the other surface are parallel to each other and positioned on opposite sides of the base member in the height direction. In addition to the reinforcing structure, the other reinforcing structure further increases the rigidity of the beam.

[0098] Another reinforcing structure may include one or more longitudinal ridges extending parallel to the longitudinal direction. One or more ridges may be positioned at a longitudinal edge of the beam. For example, another reinforcing structure may include two longitudinal ridges positioned at opposite longitudinal edges of the beam.

[0099] According to an embodiment, a beam includes a readout structure for measuring the beam's mechanical oscillations in the height direction, such as a piezoresistive readout structure and / or a Wheatstone bridge circuit. The readout structure is positioned within a curved section of the beam. Due to the reinforcement structure, stresses generated by the bending of the beam in the height direction are concentrated in the curved region. Therefore, placing the readout structure within the curved section enhances the readout device's sensitivity to beam bending.

[0100] The readout structure can be configured as a strain-sensitive readout structure, such as a piezoresistive readout structure and / or a Wheatstone bridge. Compared to optical readout, the strain-sensitive readout structure can be integrated in an area that is smaller than the area required to reflect the laser beam from the surface of the micromechanical beam. For example, optical readout requires a minimum reflective area on the back side of the beam. In high-end systems, this area is in the range of 3μm×9μm, which requires a small laser spot. Compared to readout structures placed directly on the surface of the beam, optical readout methods also require bulky optical components, their mechanical adjustment, and the ability to obtain very precise mechanical alignment. Optical components are typically bulky and take up a lot of space, thereby increasing the physical size of the instrument. This creates difficulties for fast scanning with very small beams (1μm×3μm) and for operation in closed vacuum or cryogenic cavity environments. Integrating the readout structure directly on the beam therefore allows further miniaturization of the beam.

[0101] Generally speaking, a readout structure configured as a stress-sensitive structure provides an alternative to OBD readout and provides the ability to image in different environments (such as vacuum, air, or liquid). The stress-sensitive readout structure measures the beam deflection by the stress generated in the beam within the sensor area. The stress is proportional to the thickness of the beam. A thicker beam means a higher beam stiffness (e.g., greater than 100 N / m). Such beams are generally not suitable for imaging soft samples such as polymers or biomaterials. Thick beams generally require large forces between the probe structure and the sample, which often results in severe wear or breakage of the probe structure.

[0102] The sensitivity of the stress-sensitive readout structure to the deflection of the beam (i.e., the minimum measurable deflection) depends on the stress generated in the readout structure (e.g., in a Wheatstone bridge circuit). Therefore, the readout structure should be positioned at the area of maximum stress - the top or bottom surface of the beam within the bending section positioned at the fixed end of the beam. In addition, the stress-sensitive readout structure is suitable for beams that generate high stress when the beam is deflected or bent. By strengthening the beam with a reinforcement structure between the free end and the readout structure, high stress is obtained without increasing the spring constant of the beam in the bending region. This allows the beam to remain sensitive to small forces and / or loads. For example, the beam can be configured to detect a force between 10 -15 N to 10 -18 The force between N.

[0103] The readout structure may include a Wheatstone bridge having resistors made of piezoresistive material. The Wheatstone bridge may be configured as a full Wheatstone bridge. The resistors may be thin-film resistors. The readout structure may surround an opening within the beam. Such an opening further concentrates stress in the region of the resistors of the readout structure.

[0104] In addition to or in lieu of the openings surrounded by the Wheatstone bridge, the beam can include one or more additional openings positioned proximate to the readout structure. For example, the one or more additional openings can be configured as longitudinal openings or slots. These openings can be elongated parallel to the longitudinal direction. Each additional opening can be positioned between a longitudinal edge of the beam and the readout structure. For example, the beam can have additional openings positioned on either side of the readout structure in the width direction and positioned between the longitudinal axis of the beam and the readout structure.

[0105] The openings surrounded by the readout structure and / or the additional openings can be configured to reduce the stiffness in the readout region by at most 5%, at most 2.5%, at most 1%, such as 1%, compared to the same beam without the openings. Furthermore, the openings can be configured to increase the sensitivity of the readout structure by at least 5%, such as at least 7.5%, or at least 10%, such as 10%, compared to the same beam without the openings.

[0106] The readout structure may have a bandwidth of at least 10 kHz, at least 15 kHz, or at least 20 kHz, such as 50 kHz. The vertical resolution of the readout structure may be between 0.1 nm and 25 nm, for example between 0.1 nm and 15 nm, such as 12 nm. The readout structure may be configured to detect thermally induced oscillations of the beam in air and / or liquid and / or vacuum and at room temperature under resonant conditions without the need for external actuation.

[0107] According to an embodiment, the readout structure is positioned between the two leads of the metal structure. This further concentrates the stresses resulting from bending the beam in the region of the readout structure.

[0108] According to an embodiment, the beam has at least one lateral cutout positioned in the curved section. Such a lateral cutout further concentrates the stresses generated by the bending of the beam in a region towards the center of the beam. The lateral cutout may be positioned at a longitudinal edge of the beam.

[0109] The length of the cut parallel to the longitudinal direction and the width of the cut parallel to the width direction may have a width to length ratio of at least 0.5, at least 0.75, at least 0.8, at least 0.9 or at least 0.95. In addition, the width to length ratio may be at most 2, at most 1.5, at most 1.25, at most 1.1 or at most 1.05.

[0110] The cutout may taper along the width direction. For example, the length of the cutout parallel to the longitudinal direction may be greater at the edge of the beam than towards the center of the beam. The ratio of the width to the length of the cutout may apply to the length of the cutout at the edge of the beam.

[0111] According to an embodiment, the beam has two lateral cutouts, which are positioned in the curved section at opposite side surfaces of the beam in the width direction.

[0112] A single lateral cut or two lateral cuts may narrow the width of the beam to at most 0.85 times, such as at most 0.8 times, at most 0.75 times, at most 0.7 times, or at most 0.5 times the maximum lateral width of the beam in the curved section.

[0113] According to an embodiment, over a longitudinal length at least equal to the longitudinal length of the readout structure, the width of the beam at the cutout deviates by less than 20%, such as less than 10%, less than 5%, or less than 1%, from the minimum lateral width of the beam at the cutout. Such a cutout narrows the beam over the entire longitudinal length of the readout structure and thus effectively concentrates stresses resulting from bending of the beam at the readout structure.

[0114] The present disclosure also generally relates to a micromechanical beam having at least one lateral cutout in a readout section but not featuring a stiffening structure. All other embodiments of the micromechanical beam featuring a stiffening structure disclosed in conjunction with the micromechanical beam according to the present disclosure also apply to a micromechanical beam having only at least one lateral cutout but not having a stiffening structure.

[0115] According to an embodiment, a beam comprises a drive structure configured to excite mechanical oscillations of the beam in the height direction, wherein the drive structure is positioned within a reinforced section. The beam with the drive structure is adapted for active sensing, whereby the interaction between the probe structure of the beam and the sample is sensed by a change in the resonant frequency of the beam during a driven oscillation. Integrating the drive structure directly onto the beam allows for miniaturization of the beam. Furthermore, integration of the drive structure allows for a very compact measurement setup that occupies a small space and allows for use with large beam arrays. By placing the drive structure in the reinforced section between the free end and the fixed end of the beam, the oscillations can be effectively driven by the drive structure.

[0116] The drive structure can be configured as a thermomechanical actuator. The drive structure can include a multilayer structure of at least two material layers characterized by different coefficients of thermal expansion. The different coefficients of thermal expansion of the layers cause bending of the beam due to their different elongation. This allows precise control of the beam's displacement via the electrical power dissipated in the embedded resistors formed by the stacked layers. The drive structure can include at least two thin film layers.

[0117] The drive structure may be formed by a conductive metal structure, such as a conductive metal structure located on top of the reinforcement structure. Alternatively, the drive structure may also be formed by the reinforcement structure itself. The reinforcement structure may also include the drive structure.

[0118] The drive structure can be configured to be controlled to change its temperature, e.g., heated, by internal temperature control (such as conductive and / or resistive energy transfer) or by external temperature control (such as radiative energy transfer). Thermomechanical actuation may also be referred to as bimorph actuation.

[0119] In general, the beam can be configured to oscillate at or near a resonant frequency, whereby the oscillation is driven by a drive structure to provide a relative oscillatory motion of the probe structure of the beam across the sample surface. As the beam is spaced at alternating distances from the sample surface, the oscillation amplitude and / or oscillation phase of the beam are modulated by the beam-sample interaction. The beam can be configured to be controlled using feedback signals to maintain a constant oscillation amplitude and / or oscillation phase during scanning, these feedback signals being generated (e.g., by a readout structure) in response to the tip-sample interaction. These feedback signals can then be used to determine characteristics of the sample surface.

[0120] According to an embodiment, the reinforcement structure is formed from a material that is different from the material of the drive structure.

[0121] According to an embodiment, the beam comprises at least one longitudinal slot extending over the length of the curved section. The longitudinal slot may form an opening or an additional opening extending parallel to the reinforcement element in the readout section and / or positioned next to the readout structure, such as between the readout structure and an edge of the beam.

[0122] According to an embodiment, in the reinforced section, the beam tapers in the longitudinal direction by at least 0.1 times, such as at least 0.2 times or at least 0.25 times, the width of the beam. For example, the beam may taper toward its free end. This further concentrates the mass of the beam toward its fixed end and increases the beam's bandwidth.

[0123] The present disclosure also generally relates to a mechanical beam having a tapered shape along a longitudinal direction but not featuring a stiffening structure. All other embodiments of the micromechanical beam featuring a stiffening structure disclosed in conjunction with the micromechanical beam according to the present disclosure also apply to a micromechanical beam having only a tapered shape but no stiffening structure.

[0124] The present disclosure also relates to a sensing system comprising a micromechanical beam according to the present disclosure and a control system coupled to the micromechanical beam. The control system may comprise an actuation module and / or a readout module.

[0125] The actuation module can be coupled to a drive structure and can be configured to drive the bending of the beam via the drive structure. For example, the drive structure can be configured to generate an alternating current and / or a pulsed current, which is fed to the drive structure, for example, via leads forming a metal structure of the drive structure. Thus, the leads can extend through the curved section of the beam.

[0126] A readout module can be coupled to the readout structure and can be configured to determine the bending of the beam using the readout structure. For example, the readout module can be configured to sense stress within the bending section using the readout structure. To this end, the readout module can be configured to sense a change in resistance within a Wheatstone bridge and determine the bending of the beam based on the resistance.

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

[0128] The control system may further include a control module configured to control the actuation of the beam via the actuation module and / or receive information about the bending of the beam from the readout module. The control module may be configured to drive the oscillation of the beam via the actuation module. The frequency of the oscillation may be swept across the mechanical resonance of the bending motion of the beam. The control module may be further configured to determine the amplitude and / or phase of the oscillation of the beam based on the information received via the readout module, and generate a feedback signal that controls the movement of the beam to keep the amplitude and / or phase of the oscillation constant. In addition, the control module may be configured to move the beam relative to the sample via the scanning module and output a feedback signal generated after the movement.

[0129] The present disclosure also relates to a method for manufacturing a micromechanical beam, the method comprising:

[0130] - Provide the base material for the beam;

[0131] - producing a reinforcing structure on a surface of the base material perpendicular to the height direction;

[0132] - manufacturing of independent beams from base material,

[0133] wherein the beam extends in a longitudinal direction between a fixed end and a free end,

[0134] wherein the beam has a height along a height direction perpendicular to the longitudinal direction, the height being less than the width along the width direction,

[0135] wherein the beam has a curved section and a reinforcement section, the curved section being positioned at a fixed end of the beam in the longitudinal direction, and the reinforcement section being positioned between the curved section and the free end in the longitudinal direction,

[0136] wherein the reinforcement structure is positioned within the reinforcement section, and

[0137] The reinforcement structure is configured to increase the bending stiffness of the beam in the reinforcement section for bending in the height direction.

[0138] The micromechanical beam may be a micromechanical beam according to the present disclosure. All embodiments and technical effects disclosed for the micromechanical beam are also applicable to the method, and vice versa.

[0139] According to an embodiment, manufacturing a reinforcement structure comprises:

[0140] - providing a metal structure having leads for connecting to a power supply on the surface of the base material;

[0141] - Etching the base material parallel to the height direction using the metal structure as an etching mask.

[0142] The present disclosure also relates to a method for sensing a sample using a micromechanical beam according to the present disclosure. The method includes placing a beam (such as a probe structure of the beam) in close proximity to the sample, driving the beam to oscillate, and sensing changes in the oscillation caused by the interaction between the sample and the beam. The method can be performed by a control system according to the present disclosure. All embodiments and technical effects disclosed for the control system also apply to the method for sensing, and vice versa.

[0143] Sensing a change in the oscillation may include sensing to determine a change in a resonant frequency of the oscillation resulting from the interaction between the sample and the beam.

[0144] The method may comprise driving the bending of the beam by means of a drive structure.For example, the method may comprise generating an alternating current and / or a pulsed current and feeding the current to the drive structure, for example via leads forming a metal structure of the drive structure.

[0145] The method may include determining the bending of the beam. For example, the method may include sensing stress generated after bending. The method may include sensing a change in resistance within a Wheatstone bridge and determining the bending of the beam based on the change in resistance.

[0146] The method may comprise effecting relative movement between the beam and the sample.The method may comprise moving the beam relative to the sample and / or moving the sample relative to the beam.

[0147] The method may include controlling the driving of the beam and / or receiving information about the bending of the beam. The method may include driving the beam to oscillate. The frequency of the oscillation may be swept across a mechanical resonance of the bending motion of the beam. The method may include determining the amplitude and / or phase of the oscillation of the beam and generating a feedback signal to control the movement of the beam to maintain the amplitude and / or phase of the oscillation constant. Furthermore, the method may include moving the beam relative to the sample and outputting a feedback signal generated after the movement.

[0148] A beam according to the present disclosure may also be denoted as a cantilever. BRIEF DESCRIPTION OF THE DRAWINGS

[0149] Exemplary embodiments and functions of the present disclosure are described herein with reference to the following figures, which schematically illustrate:

[0150] Figure 1 shows a side view of a micromechanical beam according to the prior art;

[0151] Figure 2 Show Figure 1 A cross-sectional view of the micromechanical beam shown;

[0152] Figure 3 A first embodiment of a micromechanical beam according to the present disclosure is shown;

[0153] Figure 4 Show Figure 3 A cross-sectional view of the micromechanical beam shown;

[0154] Figure 5 Show Figure 3 Another cross-sectional view of the micromechanical beam shown;

[0155] Figure 6 A perspective view illustrating another embodiment of a micromechanical beam according to the present disclosure;

[0156] Figure 7 shows a cross-sectional view of an embodiment of a micromechanical beam according to the present disclosure;

[0157] Figure 8 shows the bending of a micromechanical beam without a stiffening structure;

[0158] Figure 9 shows the bending of a micromechanical beam with a stiffening structure;

[0159] Figure 10 shows a detailed top view of a readout region of a micromechanical beam according to the present disclosure;

[0160] Figure 11 shows the stresses generated in the readout region of a mechanical beam having a rectangular cross-section;

[0161] Figure 12shows the differential output voltage of a readout structure as a function of deflection of a micromechanical beam according to the present disclosure;

[0162] Figure 13 shows the differential output voltage of a readout structure as a function of the deflection of a micromechanical beam having a rectangular cross-section;

[0163] Figure 14 shows the time-varying response of the output voltage of a readout structure to the instantaneous deflection of a micromechanical beam according to the present disclosure;

[0164] Figure 15 shows a first precursor structure obtained by a method for manufacturing a micromechanical beam according to the present disclosure;

[0165] Figure 16 shows a second precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0166] Figure 17 shows a third precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0167] Figure 18 shows a fourth precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0168] Figure 19 shows a fifth precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0169] Figure 20 shows a sixth precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0170] Figure 21 shows a seventh precursor structure obtained by the method for manufacturing a micromechanical beam according to the present disclosure;

[0171] Figure 22 shows an array comprising four micromechanical beams according to the present disclosure;

[0172] Figure 23 Another embodiment of a micromechanical beam according to the present disclosure is shown;

[0173] Figure 24 shows a cross section perpendicular to the longitudinal direction of an alternative embodiment of a micromechanical beam according to the present disclosure;

[0174] Figure 25 shows a plan view of another embodiment of a micromechanical beam according to the present disclosure;

[0175] Figure 26 A cross section perpendicular to the longitudinal direction of another alternative embodiment of a micromechanical beam according to the present disclosure is shown. DETAILED DESCRIPTION

[0176] Figure 1 depicts a side view of a micromechanical beam 200 according to the prior art, and Figure 2 Shown along Figure 1 Cross-sectional view of the micromechanical beam 200 along the indicated line AA. The micromechanical beam 200 has a free end 22 and a fixed end 20 fixed to a support structure 201. An individual section of the micromechanical beam 200 extends over a length 10 in the longitudinal direction 3 between the fixed end 20 and the free end 22.

[0177] Micromechanical beam 200 has a uniform rectangular cross-section over length 10 with a width 11 along width direction 4 and a height 12 along height direction 5. Width direction 4 and height direction 5 are oriented perpendicular to each other and also perpendicular to length direction 3.

[0178] A force F acting on the free end 22 of the micromechanical beam 200 parallel to the height direction 5 causes the micromechanical beam 200 to bend by a distance z along the height direction 5. For the periodic force F, the micromechanical beam 200 oscillates about its equilibrium position.

[0179] For small amplitudes, the vibrating micromechanical beam 200 behaves like a spring-mass system defined by its spring constant k and equivalent mass m, such that the resonant frequency is given by:

[0180]

[0181] For those with Figure 2 For the micromechanical beam 200 of rectangular cross section shown, the equivalent spring constant of the first bending mode is:

[0182]

[0183] Where L is the length 10, w is the width 11, and h is the height 12. E represents the Young's modulus of the beam material, which is a measure of the elasticity of the material of the micromechanical beam 200.

[0184] The static deflection z of the uniform micromechanical beam 200 for a lateral force F applied to the free end 22 can be calculated using the classical Euler-Bernoulli beam theory. Figure 1 and Figure 2 The rectangular cross section shown has a bending deflection z under a force load F.

[0185]

[0186] The calculation of bending forces, such as those generated when the micromechanical beam 200 approaches the probe surface with its free end 22, requires knowledge of both the mechanical properties of the beam material and the geometric arrangement of the micromechanical beam 200, also known as the second moment of area or area moment of inertia I. The flexural stiffness of the micromechanical beam 200 is the tensor product (E×I) of Young's modulus and the area moment of inertia. Young's modulus describes a material property 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

[0187]

[0188] And the bending stiffness is

[0189]

[0190] Brownian motion causes the micromechanical beam 200 to oscillate spontaneously, so that each oscillation mode of the micromechanical beam 200 has the same average thermal energy k B T. These thermal fluctuations are called thermomechanical noise. The resulting oscillatory motion over time can be Fourier transformed to obtain the power spectral density (PSD) of the motion in the frequency domain. For example, the Brownian motion of the micromechanical beam 200 in air is caused by the random momentum transferred to the micromechanical beam 200 by the surrounding molecules.

[0191] The dynamics of the micromechanical beam 200 is expressed as a resonator with a total system energy, and the average values of the kinetic energy term and the potential energy term are both

[0192]

[0193] According to the equipartition theorem, where T is the temperature (in Kelvin) and k B represents the Boltzmann constant, k B =1.3805×10 –23 J / K. The potential energy is then equal to

[0194]

[0195] Where ω0=(k / m) 1 / 2 is the angular resonant frequency of the micromechanical beam 200. The angle brackets indicate the average value over time. Rearranged to obtain the thermal noise amplitude of the micromechanical beam 200 in the height direction 5. Then, the following terms can be used to calculate the thermal noise amplitude of the micromechanical beam 200 according to the temperature T and the average displacement Determine the spring constant k:

[0196]

[0197] The average displacement is given by The following terms are given:

[0198]

[0199] For a micromechanical beam 200 made of silicon and having a length 10 of 5 μm and a cross section of 100 nm×50 nm, the mass m is about m≈47×10 -18 kg, and the resonant frequency is about f res ≈100MHz, the average displacement is equal to <z>≈40fm. The ground state energy of a beam at frequencies of hundreds of MHz can be equivalent to a temperature in milliK.

[0200] The maximum achievable scan rate is determined by the maximum achievable speed with which the micromechanical beam 200 can move relative to the sample. In the low damping limit, this speed is given by:

[0201]

[0202] In the highly damped limit, the velocity is given by:

[0203]

[0204] Therefore, D represents damping, and S s Represents surface elasticity.

[0205] From these equations, it can be inferred that if the mass of micromechanical beam 200 is reduced (eg, by making micromechanical beam 200 smaller), the maximum achievable scanning speed increases.

[0206] Figure 3 A first embodiment of a micromechanical beam 1 according to the present disclosure is depicted. Figure 4 Depicts the Figure 3 A cross-section of the micromechanical beam 1 perpendicular to the longitudinal direction 3 along the line AA is shown, and Figure 5 Depicts the Figure 3 Another cross-sectional view of the micromechanical beam 1 perpendicular to the longitudinal direction 3 along the line BB is shown. With regard to the undisclosed differences, the micromechanical beam 1 is as for Figure 1 and Figure 2 The illustrated micromechanical beam 200 may be configured as disclosed herein, and vice versa.

[0207] Similar to beam 200, micromechanical beam 1 extends over a length 10 between a fixed end 20 and a free end 22, parallel to a longitudinal direction 3. Fixed end 20 is integrally connected to support structure 201. At free end 22, micromechanical beam 1 includes a probe structure 7 configured as a tip that protrudes from micromechanical beam 1 in a height direction 5 and is located within a probe section 25 of 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.

[0208] Micromechanical beam 1 includes a base member 50 extending from fixed end 20 to free end 22. Base member 50 is configured as a plate having a height 51 in height direction 5 that is less than a length 10 parallel to length direction 3 and a width 11 of base member 50 parallel to width direction 4. Base member 50 is made of silicon and formed as a single, uniform, one-piece member. Probe structure 7 is placed on surface 52 of base member 50 at free end 22.

[0209] Directly above the support structure 201, the micromechanical beam 1 comprises a curved section 30 having a length 31 parallel to the longitudinal direction 3. Between the curved section 30 and the free end 22, the micromechanical beam 1 comprises a reinforcing section 40 extending over a length 41 parallel to the longitudinal direction 3. Thus, the reinforcing section 40 is positioned at a distance 49 from the curved section 30. The width 11 of the base element 50 within the reinforcing section 40 decreases gradually from a maximum width 56 to a minimum width 57 towards the free end 22 of the micromechanical beam 1. Figure 3 In the case of the embodiment shown, the base element 50 comprises a straight edge 54 in the region between a maximum width 56 and a minimum width 57 .

[0210] In the reinforcement section 40, the micromechanical beam 1 comprises a reinforcement structure 100. Figure 4 As can be seen, the reinforcement structure 100 is placed on the surface 52 of the base element 50, which surface also carries the probe structure 7. The reinforcement structure 100 is materially uniformly joined to the base element 50. The base element 50 and the reinforcement structure 100 thus form a single piece.

[0211] The reinforcing structure 100 comprises a plurality of longitudinal ridges 110 extending parallel to one another along the longitudinal direction 3 and alternately joined to one another at their longitudinal ends 107 to form a meandering structure extending from a first end 108 to a second end 109 .

[0212] As from Figure 4 As can be seen, the ridges 110 have a substantially rectangular cross-section in a plane perpendicular to the longitudinal direction 3, wherein 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 one another by a distance 122 along the width direction 4, such that gaps 120 are formed between the ridges 110. Generally speaking, the height 102 of the reinforcement structure 100 is between 0.25 and 5 times the height 51 of the base member 50.

[0213] The reinforcement structure 100 has a length 101 along the longitudinal direction 3 and a width 104 along the width direction 4. The length 101 of the reinforcement structure 100 is equal to the length 41 of the reinforcement section 40. The width 104 of the reinforcement structure 100 is smaller than the width 11 of the base element 50 within the reinforcement section 40.

[0214] The length 101 of the reinforcement structure 100 is 0.5 times the length 10 of the micromechanical beam 1. Generally, the length 101 of the reinforcement structure 100 may be between 0.25 and 0.8 times the length 10 of the micromechanical beam 1, such as between 0.4 and 0.6 times.

[0215] The width 104 of the reinforcement structure 100 is equal to 0.9 times the minimum width 57 of the micromechanical beam 1 within the reinforcement section 40. Generally, the width 104 of the reinforcement structure 100 can be between 0.5 times and 1 times the minimum width 57 of the micromechanical beam 1 within the reinforcement section 40, such as between 0.8 times and 0.95 times. The width 104 of the reinforcement section 100 is equal to 0.6 times the maximum lateral width 36 of the micromechanical beam 1. Generally, the width 104 of the reinforcement section 100 can be between 0.3 times and 0.8 times the maximum lateral width 36, such as between 0.5 times and 0.7 times.

[0216] At a top surface 79 of the stiffening structure 100 (the top surface 79 facing away from the base element 50), the micromechanical beam 1 includes a drive structure 70 separated from the stiffening structure 100 by an insulating layer 78. The insulating layer 78 has a height 73 that is less than the height 51 of the base element 50. For example, the height 73 of the insulating layer 78 can be between 0.1 and 0.5 times the height 51 of the base element 50, such as 0.3 times.

[0217] The drive structure 70 has a height 75 that is less than the height 51 of the base member 50. For example, the height 75 of the drive structure 70 may be between 0.1 and 0.3 times the height 51 of the base member 50, such as 0.2 times.

[0218] The drive structure 70 is made of metal and constitutes a metal structure. The drive structure includes a first metal layer 72 positioned adjacent to an insulating layer 78 and a second metal layer 74 positioned on the first metal layer 72 on the side opposite to 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 have different thermal expansion coefficients.

[0219] Drive structure 70 is configured to be resistively heated by a current flowing through meandering drive structure 70. Upon heating of drive structure 70, first metal layer 72 and second metal layer 74 expand by different amounts, causing drive structure 70 and thus micromechanical beam 1 to bend along height direction 5.

[0220] Total height 12 of micromechanical beam 1 within stiffening section 40 is the sum of height 51 of base element 50, height 102 of stiffening structure 100, height 73 of insulating layer 78, and height 75 of drive structure 70. Insulating layer 78 may also be an acrylic layer or a parylene layer.

[0221] In order to connect the drive structure 70 to a power source, the drive structure 70 includes two leads 76 which extend from the reinforcement section 40 through the curved section 30 to the support structure 201. Figure 5 It can be seen that the lead 76 has a width 99 that is parallel to the width direction 4. Thus, the width 99 is greater than the width 112 of the ridge 110 of the reinforcement structure 100.

[0222] The probe section 25 , the reinforcement section 40 and the bending section 30 are spaced apart from each other along the longitudinal direction 3 and are positioned next to each other along the longitudinal direction 3 .

[0223] As from Figure 5 As can be seen, the leads 76 are each positioned on top of a reinforcement element 97. The reinforcement element 97 is materially uniformly bonded to the base member 50 such that the reinforcement element 97 and the base member 50 form a one-piece component. The reinforcement element 97 has a height 98 that is equal to the height 102 of the reinforcement structure 100. The reinforcement element 97 is configured as a single ridge extending parallel to the longitudinal direction 3 within the edge region 58 of the base member 50. The leads 76 are separated from the reinforcement element 97 by an insulating layer 78.

[0224] exist Figure 5 In the illustrated embodiment, the lead 76 also features a first metal layer 72 and a second metal layer 74 made of different materials. In other embodiments, the lead 76 may also include a single metal layer.

[0225] Within the curved section 30 , the micromechanical beam 1 comprises a readout structure 90 . The readout structure 90 is placed within a readout region 96 , wherein the readout region 96 is positioned at the center of the micromechanical beam 1 along the width direction 4 .

[0226] At the center of the readout structure 90, the base member 50 includes an opening 94 configured as a through hole through the base member 50. The opening 94 has a width 95 parallel to the width direction 4 that is equal to 0.5 times the height 51 of the base member 50. Generally speaking, the width 95 of the opening 94 can be between 0.25 times and 1 times the height 51 of the base member 50.

[0227] On either side of the readout structure 90, the base member 50 includes openings 38. Each opening 38 is configured as a longitudinal slot oriented parallel to the longitudinal direction 3. Each opening 38 is positioned between an edge of the base member 50 that delimits the base member 50 in the width direction 4 and the readout structure 90. The openings 38 extend along the entire readout region 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 equal to 0.5 times the height 51 of the base member 50. Generally speaking, the width 32 can be between 0.25 times and 1 times the height 51 of the base member 50.

[0228] At both lateral sides of the base member 50 in the width direction 4, the base member 50 includes cutouts 34. The cutouts 34 narrow the width 11 of the base member 50 in the bend region 32 from a maximum lateral width 36 to a minimum lateral width 35. The minimum lateral width 35 is 0.7 times the maximum lateral width 36. Generally, the minimum lateral width 35 can be between 0.4 and 0.9 times the maximum lateral width 36, such as between 0.6 and 0.8 times.

[0229] The length of the cutout 34 at the lateral position corresponding to the maximum width 36 is equal to the length 31 of the curved region 30. The base element 50 tapers to a minimum width 35 over a length 37 within the cutout 34. The length 37 is therefore at least equal to the length 92 of the readout structure 19 parallel to the longitudinal direction 3.

[0230] Figure 6 A perspective view of another embodiment of a micromechanical beam 1 according to the present disclosure is shown. Figure 6 The illustrated implementation is for example directed to Figures 3 to 5 The illustrated embodiments are configured as disclosed, and vice versa. Figures 3 to 5 The reinforcement structure 100 of the micromechanical beam 1 shown comprises six ridges 110, but Figure 6 The reinforcement structure 100 of the illustrated micromechanical beam 1 comprises ten ridges 110 .

[0231] As from Figure 6 It can be seen that the support structure 201 is positioned on the surface of the base element 50 opposite the surface 52 carrying the reinforcement structure 100 and the probe structure 7 .

[0232] Figure 6 The micromechanical beam 1 shown has a length 10 of 165 μm, a maximum lateral width 36 of 135 μm, a minimum lateral width 35 of 115 μm, and a base element height 51 of 1.13 μm. The height of the probe structure is 6.6 μm. The effective mass density of the micromechanical beam 1 is 2920 kg / m 3 , and the effective Young's modulus is E = 150 GPa. This results in a resonant frequency of 188.1 kHz and a spring constant of k = 1.2 N / m.

[0233] The width 112 of the ridge 110 is 2 μm, and the width 122 of the gap 120 is 3 μm. In addition, the ridge 110 has a height 102 of 4 μm. The lateral width 99 of the lead 76 is equal to 6.5 μm. In addition, the width 95 of the central opening 94 in the readout structure 90 is 7 μm, and the width 32 of the longitudinal opening 38 is 4 μm.

[0234] In another embodiment, Figure 6 The micromechanical beam 1 shown has a length 10 of 350 μm, a maximum lateral width 36 of 185 μm, a minimum lateral width 35 of 140 μm, and a base element height 51 of 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 / m 3 , and the effective Young's modulus is E = 150 GPa. This results in a resonant frequency of 69.12 kHz and a spring constant of k = 2.29 N / m.

[0235] The width 112 of the ridge 110 is 5.2 μm, and the width 122 of the gap 120 is 4.8 μm. In addition, the ridge 110 has a height 102 of 4.5 μm. The lateral width 99 of the lead 76 is equal to 9.9 μm. In addition, the width 95 of the central opening 94 in the readout structure 90 is 6 μm, and the width 32 of the longitudinal opening 38 is 5.2 μm.

[0236] In another embodiment, the micromechanical beam 1 may comprise a stiffening structure 100 having a height 102 of 3 μm and a base element 50 having a height 51 of 3 μm. The micromechanical beam 1 then has a resonance frequency of 1800 kHz and a mechanical bandwidth of 6.4 kHz.

[0237] Figure 7 A cross-sectional view of an embodiment of a micromechanical beam 1 comprising nine ridges 110 is depicted. With respect to undisclosed differences, Figure 7 The implementation shown is for example for Figures 3 to 5 The illustrated embodiments may be configured as disclosed, and vice versa.

[0238] Figure 6 The second moment of area I of the cross section shown r equal

[0239]

[0240] Where w represents the width 104 of the reinforcement structure 100, t represents the width 112 of the ridge 110, and h t The height 102 of the reinforcement structure 100 and h p is the height 51 of the base element 50 .

[0241] Figure 8 and Figure 9 The effect of the reinforcement structure 100 on the stresses generated in the curved section 30 of the micromechanical beam 1 according to the present disclosure is illustrated. Figure 8 shows the bending of the micromechanical beam 1 without the reinforcement structure 100 when deflected by a distance z in the height direction 5 , and Figure 9 Shown is a reinforced structure ( Figure 9 The bending of the micromechanical beam 1 (not visible in the figure) when deflected by a distance z. The amount and distribution of stress generated in the micromechanical beam 1 are indicated by the shading of the micromechanical beam 1. Figure 8 Compared to the micromechanical beam 1 shown, although Figure 9 The stress in the micromechanical beam 1 shown is increased at least 18 times within the curved section 30 , but the stress decreases by at least an order of magnitude further away from the curved section 30 toward the free end 22 of the micromechanical beam 1 .

[0242] Figure 10 A detailed top view of a readout region 96 having a readout structure 90 is shown. The readout structure 90 is configured as a Wheatstone bridge. The readout structure includes a first contact 171 and a second contact 172, wherein the second contact 172 is positioned opposite the first contact 171 relative to the opening 94 in the micromechanical beam 1. Thus, the first contact 171 and the second contact 172 are positioned at opposite sides of the rectangular opening 94.

[0243] In addition, the readout structure 90 includes a third contact 173 and a fourth contact 174. The third contact 173 and the fourth contact 174 are positioned at the remaining opposite sides of the opening 94. The third contact 173 is electrically coupled between the first contact 171 and the second contact 172. A first resistor 175 connects the first contact 171 to the third contact 173, and a second resistor 176 connects the second contact 172 to the third contact 173. In addition, the fourth contact 174 is electrically coupled between the first contact 171 and the second contact 172 in parallel with the third contact 173. Therefore, 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.

[0244] Therefore, the second resistor 176 and the fourth resistor 178 are oriented parallel to the longitudinal direction 3, and the first resistor 175 and the third resistor 177 are oriented parallel to the width direction 4. The resistors 175, 176, 177, 178 are configured as piezoresistive elements having resistance values that vary according to stress generated in the resistors 175, 176, 177, 178.

[0245] A first contact 171 is connected to ground, and a second contact 172 is connected to a voltage line for connecting to a voltage source that provides an operating voltage for the readout structure 90. A third contact 173 is connected to a first sense line for connecting to a first input of a readout module configured to determine the resistance of the readout structure 90. A fourth contact 174 is connected to a second sense line for connecting to a second input of the readout module.

[0246] As from Figure 10 It can be seen that the stress 180 (which is given by Figure 10 1 (as indicated by the shading of beam 1 in FIG), resistors 175 , 176 , 177 , and 178 are concentrated along the readout structure 90 .

[0247] For comparison, Figure 11 The stress 180 generated in the readout region 96 of a micromechanical beam 1 having a rectangular cross section perpendicular to the longitudinal direction 3 and without the features of the reinforcement structure 100, the cutout 34 in the bending region 30, and the taper from the maximum width 36 to the minimum width 57 is depicted. Figure 11 It can be seen that the stress 180 generated in the readout region 96 around the readout structure 90 is less than that in the embodiment according to the present disclosure and Figure 10 Stresses 180 induced in micromechanical beam 1 are shown.

[0248] The sensitivity of the piezoresistive readout structure 90 is defined as the slope of the characteristic output curve It is defined as the change in output voltage dV due to a load force for a given deflection dz. It also represents the minimum input of beam deflection generated by a standard force load that will produce a measurable output voltage, or the minimum load force required to produce a measurable output voltage.

[0249] Figure 12 Describes the Figure 11 The deflection 401 of the micromechanical beam 1 changes the differential output voltage 402 of the readout structure 90, and Figure 13 Describes the Figure 10 The differential output voltage 402 of the readout structure 90 is shown as a function of the deflection 401 of the micromechanical beam 1 according to the present disclosure. As can be seen from these figures, the micromechanical beam 1 according to the present disclosure has The sensitivity or characteristic output curve of Figure 11 The micromechanical beam 1 shown has sensitivity or characteristic output curve.

[0250] The piezoresistive readout response time is defined as the time required for the differential output voltage measured at the sense lines of the piezoresistive readout structure 90 to change from an initial value to a value within a tolerance band around a set final voltage value.

[0251] Figure 14 The response of the output voltage 402 of the readout structure 90 according to the present disclosure to the instantaneous deflection 401 of the micromechanical beam 1 over time 405 is depicted. The micromechanical beam 1 is thus deflected by applying a step DC voltage to the lead 76 of the drive structure 70. Therefore, the effective deflection of the micromechanical beam 1 in the height direction 5 is about 1200 nm, and the spring constant of the micromechanical beam is equal to 2.85 N / m. As can be seen from Figure 14 It can be seen that the readout response time is less than 20 μs, which results in a bandwidth greater than 20 kHz. If the force applied to the micromechanical beam 1 when activating the oscillating motion in the height direction 5 is less than 10 nN, the readout structure 90 has a step response time of approximately 50 μs.

[0252] Figure 15 A first precursor structure 500 is depicted which is obtained when carrying out the method for manufacturing a micromechanical beam 1 according to the present disclosure.

[0253] The method includes providing a substrate structure including a substrate layer 501, an insulating layer 502 positioned on top of the substrate layer 501 in a height direction 5, and a beam layer 503 positioned on top of the insulating layer 502 in the height direction 5. The substrate structure is configured as a silicon-on-insulator (SOI) wafer. The substrate layer 501 and the beam layer 503 are made of silicon, and the insulating layer 502 is configured as an oxide layer.

[0254] The base structure is then provided with a further insulating layer 505 placed on top of the beam layer 503. The further insulating layer 505 is configured as an oxide layer.

[0255] The insulating layer 502 is configured as a buried 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 side of the base layer 501 facing away from the beam layer 503 is covered with 60 nm of CVD silicon nitride. Another insulating layer 505 is configured as thermal SiO2 having a height of 300 nm.

[0256] The probe structure 7 is formed by a micromachining process. This process involves applying a probe mask 510 onto the further insulating layer 505 and structuring the probe mask 510 by photolithography. This results in Figure 15 The first precursor structure is shown.

[0257] The probe mask 510 has a height of 1 μm.

[0258] The probe structure 7 is then defined by etching (such as by RIE etching and / or wet etching) the beam layer 503. Thus, the probe structure 7 is defined by an undercut formed in the beam layer 503 below the probe mask 510.

[0259] During the etching step, the pattern of the probe mask is transferred into the insulating layer 505 by wet etching, and in the following step, the probe structure 7 is formed by wet etching, for example in a hot aqueous solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

[0260] 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 515 serves as a passivation layer. The protective layer 515 is configured as a SiO2 / Si3N4 layer. The protective layer 515 has a height of 150 nm. The protective layer is configured as a zero-stress Si3N4 layer. The protective layer 515 is formed by plasma-enhanced chemical vapor deposition and passivates the upper side of the base structure.

[0261] This leads to Figure 16 A second precursor structure 520 is shown.

[0262] Figure 17 A third precursor structure 525 obtained by the method for manufacturing a micromechanical beam 1 according to the present disclosure is shown.

[0263] The third precursor structure 525 is formed from the second precursor structure 520 by applying a patterned photoresist on top of the protective layer 515. Furthermore, the electrical connection to the readout structure 90 is defined by injecting carriers into the beam layer 503. The protective layer 515 and the patterned photoresist thus serve as a mask for the injection of carriers. The injection is performed as a boron injection at 30 keV. Afterwards, the patterned photoresist is removed. This is performed by microwave O2 plasma stripping, followed by an annealing process at 1050°C for 30 minutes.

[0264] The method then includes defining resistors 175, 176, 177, 178 of the readout structure 90. These resistors are exemplarily defined by implanting boron at 20 keV under ultra-high vacuum, followed by a rapid thermal anneal (RTA) at 1100° C. for 30 s. Alternatively, resistors 175, 176, 177, 178 may be defined by implantation and annealing.

[0265] In a subsequent photolithography step, contact holes are defined and etched in the protective layer 515 to allow connection of the p+ diffusion regions to the metal paths. The etching is performed as a plasma etching process.

[0266] After performing these steps of the method, we obtain Figure 17 A third precursor structure 525 is shown.

[0267] Figure 18 A fourth precursor structure 530 obtained when carrying out the method for manufacturing a micromechanical beam 1 is depicted.

[0268] The fourth precursor structure 530 is obtained from the third precursor structure 525 by depositing a metal layer 532 on top of the protective layer 515. The metal layer 532 is deposited by magnetron sputtering. The metal layer has a thickness of 800 nm. The metal layer 532 is configured as an Al / Si / Mg thin film.

[0269] The method then includes defining a drive structure 70 from metal layer 532. Drive structure 70 is defined by photolithography using a photoresist mask, followed by metal etching. The step of defining drive structure 70 also includes defining leads 76. Leads 76 are also defined by photolithography, followed by metal etching. Furthermore, the method includes defining bonding features for connecting micromechanical beam 1 to a control system, also by photolithography and subsequent metal etching.

[0270] Subsequently, annealing was performed in a N2 atmosphere at 410°C for 50 minutes.

[0271] The method then obtains Figure 18 A fourth precursor structure 530 is shown.

[0272] Subsequently, another protective layer is deposited. The other protective layer is configured as a low-stress oxide-nitride layer. The other protective layer is deposited by plasma enhanced chemical vapor deposition (PECVD).

[0273] In another step, the reinforcement structure 100 is defined. The reinforcement structure 100 is defined by etching the beam layer 503. The mask for etching the reinforcement structure 100 is thus defined by the drive structure 70, which provides a patterned metal film as a hard mask. In other embodiments of the method, when the step of defining the reinforcement structure 100 is performed, the photoresist mask used to define the drive structure 70 may still be present.

[0274] Alternatively, a separate mask for etching the reinforcement structure 100 may also be formed by photolithography. For example, the mask may be formed of patterned photoresist.

[0275] The etching of the reinforcement structure 100 is performed as a dry etch. This etching involves removing another protective layer in a FH3 / Ar gas mixture. Subsequently, the silicon etching of the beam layer 503 is performed using a so-called gas cutting process. During the etching, the beam layer 503 is thinned, except for the areas masked by the etching mask. The etching mask also serves to protect the probe structure 7 during the etching.

[0276] This leads to Figure 19 A fifth precursor structure 535 is shown.

[0277] Subsequently, the substrate element 50 is defined by removing the substrate layer 501 in the area occupied by the independent part of the micromechanical beam 1. This removal includes a step of performing photolithography at the back side of the substrate layer 501 to define the independent part. Subsequently, the substrate layer 501 is etched to form a membrane comprising the independent part of the micromechanical beam 1. First, the etching is performed as a wet etching of CVD silicon nitride at the back side of the substrate layer 501. This is followed by etching of the substrate layer 501 using a deep anisotropic silicon etch. The etching is performed in a hot aqueous solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH). The etching stops at the insulating layer 502, which is configured as a buried SOI oxide film (BOX). The photolithography at the back side of the substrate layer 501 is aligned with the structure placed at the front side of the substrate layer 501 to obtain the desired beam design. The remaining portion of the substrate layer 501 positioned at the fixed end 20 of the micromechanical beam 1 forms the support structure 201.

[0278] This leads to Figure 20 A sixth precursor structure 536 is shown.

[0279] The method then involves defining the micromechanical beam 1. This involves a photolithography step on the top surface and a subsequent dry etching step. In the following photolithography and dry etching steps, the contours of the micromechanical beam 1 are defined. During etching, HF vapor etching is used to strip away the BOX and oxide protecting the probe structure 7.

[0280] The final step of microwave plasma stripping removes the photoresist from the previous lithography step. This results in Figure 21 A sixth precursor structure 536 is shown.

[0281] Subsequently, the micromechanical beam 1 including the support structure 201 is mechanically separated from the rest of the base layer 501 .

[0282] In the case of all embodiments, the micromechanical beam 1 will also be part of an array of a plurality of micromechanical beams 1. In the case of these embodiments, the array of micromechanical beams 1 is manufactured in parallel and is mechanically separated from the rest of the silicon frame.

[0283] Figure 22 Such an array is shown comprising four micromechanical beams 1 , which are arranged next to each other in a width direction 4 . The micromechanical beams 1 are connected via a support structure 201 .

[0284] Figure 22 Each of the micromechanical beams 1 shown has a length 10 of 91 μm, a maximum lateral width 36 of 56 μm, a minimum lateral width 35 of 41 μm, and a base element height 51 of 1.8 μm. The height of the probe structure is equal to 5.6 μm. The effective mass density of the micromechanical beam 1 is equal to 2920 kg / m 3 , and the effective Young's modulus is E = 150 GPa. This results in a resonant frequency of 1.21 MHz and a spring constant of k = 1.24 N / m.

[0285] The width 112 of the ridge 110 is 2.3 μm, and the width 122 of the gap 120 is 2.1 μm. In addition, the ridge 110 has a height 102 of 3.7 μm. The lateral width 99 of the lead 76 is equal to 5.6 μm. In addition, the width 95 of the central opening 94 in the readout structure 90 is 5.2 μm, and the width 32 of the longitudinal opening 38 is 3.2 μm.

[0286] Figure 23 Another embodiment of a micromechanical beam 600 according to the present disclosure is shown. With respect to undisclosed differences, the micromechanical beam 600 is configured as disclosed for the micromechanical beam 1, and vice versa. The micromechanical beam 600 includes a base element 50 having straight edges along the longitudinal direction 3 and, therefore, not having a tapered feature from a maximum width 36 to a minimum width 57.

[0287] Figure 24 A cross section perpendicular to the longitudinal direction 3 of an alternative embodiment of the micromechanical beam 1 is shown. With regard to the undisclosed differences, Figure 24 The micromechanical beam 1 shown is configured as disclosed for the other micromechanical beams 1, 600 according to the present disclosure, and vice versa. In addition to the reinforcement structure 108 on the surface 52 of the base element 50, the micromechanical beam 1 also includes a further reinforcement structure 150. With respect to undisclosed differences, the further reinforcement structure 150 is configured as disclosed for the reinforcement structure 100, and vice versa.

[0288] Another reinforcing structure 150 is positioned at another surface 53 of the base member 50, wherein the other surface 53 is positioned opposite to the surface 52 in the height direction 5. The other reinforcing structure 150 includes a ridge 110, wherein the ridge 110 of the other reinforcing structure 150 extends from the surface 53 in the opposite direction as the ridge 110 of the reinforcing structure 100 extends from the surface 52.

[0289] Another reinforcement structure 150 includes two ridges 110. The ridges 110 are positioned at the edges of the base element 50 in the width direction 4. Thus, the ridges 110 extend parallel to the longitudinal direction 3. Similar to the ridges 110 of the reinforcement structure 100, the ridges 110 of the other reinforcement structure 150 carry a metal layer 70, which is separated from the ridges 110 by an insulating layer 78. The metal layer 70 and the second insulating layer 78 are configured as disclosed for the corresponding layers 70, 78 placed on top of the ridges 110 of the reinforcement structure 100.

[0290] Figure 25 A plan view of another micromechanical beam 650 according to the present disclosure is depicted. With respect to undisclosed differences, the micromechanical beam 650 is configured as disclosed for the micromechanical beams 1, 600, and vice versa.

[0291] Another micromechanical beam 650 comprises a triangular shape. In the case of this embodiment, the other micromechanical beam 650 is configured as an equilateral triangle. The base of the triangle is oriented parallel to the width direction 4 at the support structure 201. The probe structure 7 is positioned at the corner of the triangle opposite to the base.

[0292] Another micromechanical beam 650 includes a straight edge 54 extending from the curved section 30 to the probe section 25. Thus, the straight edge 54 extends to the longitudinal position of the probe structure 7 in the longitudinal direction 3. Furthermore, the straight edge 54 extends to the longitudinal position of the readout structure 90 in the longitudinal direction 3. Thus, the straight edge 54 covers more than half of the extent of the readout structure 96 along the longitudinal direction 3.

[0293] Opening 38 is positioned within curved section 30 and between readout region 96 and straight edge 54. Opening 38 has a triangular shape. In the illustrated embodiment, opening 38 is configured as a right triangle. The respective hypotenuse of the triangle is oriented parallel to edge 54. Another micromechanical beam 650 does not feature a lateral cutout 34 within curved region 30.

[0294] Another micromechanical beam 650 comprises a stiffening structure 100 having four ridges 110. The joints at the longitudinal ends 107 of the stiffening structure 100 are curved. Thus, the joints are configured with a circular cross section.

[0295] The micromechanical beam 650 has a length of 70 μm in the longitudinal direction 3. The resistor of the readout structure 90 has a lateral width of 4.5 μm, and the ridge 110 has a lateral width of 5 μm. The ridge 110 has a metallization made of aluminum.

[0296] In other embodiments, the micromechanical beam 650 can also be configured without the stiffening structure 100. In this case, it can exemplarily include a meandering conductive structure that connects the lead 76 between the probe section 25 and the base element 201. Similar to the embodiment featuring the stiffening structure 100, this conductive structure can then be configured as a heating element to excite the oscillation of the micromechanical beam 650.

[0297] In all cases, the micromechanical beam 1, 600, 650 comprises a patterned multilayer structure comprising a reinforcement structure 100. The multilayer structure is patterned homogeneously in the height direction 5. The gaps 120 between the ridges 110 of the reinforcement structure 100 are formed by areas where the multilayer structure has been removed.

[0298] exist Figure 4 In the case of the micromechanical beam 1 shown, the multilayer structure comprises a metal structure 70 having a first metal layer 72 and a second metal layer 74 , an insulating layer 78 and a portion of the base material, which portion is given by a structured section of the base material located on top of the surface 52 of the base element 50 in the height direction 5 .

[0299] In the case of alternative embodiments of the aforementioned micromechanical beams 1, 600, 650, the reinforcement structure 100 may also include an insulating layer 78 and / or a metal structure 70. The dimensions and material properties of the reinforcement structure 100 (such as bending stiffness, cross-sectional area perpendicular to the longitudinal direction 3, the second moment of area about an axis parallel to the width direction 4, and the height 102) may then be at least partially given by the corresponding dimensions and material properties of the insulating layer 78 and / or the metal structure 70.

[0300] In the case of further alternative embodiments of the aforementioned micromechanical beams 1, 600, 650, the reinforcement structure 100 can be formed separately from the material of the base element 50 and / or the surface 52 of the base element 50 carrying the reinforcement structure 100 can be configured as a flat surface over the entire area covered by the reinforcement structure 100. The material 50 of the base element may not contain any sections structured in the height direction 5.

[0301] For example, the reinforcement structure 100 may not include a portion having the same material as the base member 50. The reinforcement structure 100 may only include a layer having a material different from that of the base member 50.

[0302] Figure 26 A cross section perpendicular to the longitudinal direction 3 of a micromechanical beam 700 is shown, which is another alternative embodiment of the micromechanical beam 1. With regard to the undisclosed differences, Figure 26 The illustrated micromechanical beam 700 is configured as disclosed for the other micromechanical beams 1 , 600 , 650 according to the present disclosure, and vice versa.

[0303] In the case of micromechanical beam 700 , reinforcement structure 100 is made of a material that is different from the base material of base element 50 .

[0304] The reinforcement structure 100 includes a metal structure 70 and an insulating layer 78 located between the metal structure 70 and the base element 50 (i.e., consists of the metal structure and the insulating layer). With respect to undisclosed differences, the metal structure 70 and the insulating layer 78 are configured as disclosed for the metal structure 70 and the insulating layer 78 of the micromechanical beam 1, or vice versa. In alternative embodiments, the reinforcement structure 100 can also include only the metal structure 70 without the insulating layer 78. The insulating layer 78 can then be a homogeneous layer located in a plane perpendicular to the height direction 5.

[0305] The metal structure 70 includes only a single metal layer. The metal layer may be formed of or contain tungsten, a tungsten alloy, molybdenum, a molybdenum alloy, or an aluminum-magnesium alloy. The insulating layer 78 may be formed of or contain SiO2.

[0306] In all embodiments, the height 75 of the metal structure 70 can be between 0.7 μm and 5 μm. The height 75 can be 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 can be at most 1 μm, at most 1.5 μm, at most 2 μm, at most 2.5 μm, at most 3 μm, at most 3.5 μm, at most 4 μm, at most 4.5 μm, or at most 5 μm. The width 112 of the ridge of the metal structure 70 can be between 0.7 μm and 2 μm. The width 112 can be 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 may be at most 0.8 μm, at most 1 μm, at most 1.25 μm, at most 1.5 μm, at most 1.75 μm, or at most 2 μm.

[0307] In all embodiments, the height 73 of insulating layer 78 can be between 0.7 μm and 2 μm. Height 73 can be 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. Height 73 can be at most 0.8 μm, at most 1 μm, at most 1.25 μm, at most 1.5 μm, at most 1.75 μm, or at most 2 μm. The width of the ridge of insulating layer 78 is equal to the width 112 of the ridge of metal structure 70.

[0308] The width 122 of the gaps 120 between the ridges 110 of the metal structures 70 can be between 1 μm and 3 μm. For example, the width 122 can be 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 can be at most 1.25 μm, at most 1.5 μm, at most 1.55 μm, at most 2 μm, at most 2.25 μm, at most 2.5 μm, at most 2.75 μm, or at most 3 μm.

[0309] Alternative metal structures 70 of other embodiments of the micromechanical beam 1 , 600 , 650 may also comprise only such a single metal layer.

[0310] All metal structures 70 having only a single metal layer can be configured as a drive structure. Therefore, the metal structure 70 can have a different thermal expansion coefficient than the base element 50. Due to the different thermal expansion coefficients of the single metal layer and the base element 50, this can cause bending of the micromechanical beam 1, 600, 650.

[0311] The micromechanical beam 700 exemplarily includes a cover layer 80. The cover layer 80 covers the reinforcement structure 100. Furthermore, the cover layer 80 covers the entire reinforcement section 40. Additionally, the cover layer 80 exemplarily covers the entire micromechanical beam 700.

[0312] The cover layer 80 is made of silicon nitride. Exemplarily, the cover layer is made of Si3N4. The cover layer 80 has been formed by atomic layer deposition.

[0313] The capping layer 80 has a thickness of 20 nm. Exemplarily, the thickness of the capping layer 80 is less than 10%, such as less than 5%, for example less than 3%, of the thickness 75 of the metal structure 70 and / or the thickness 102 of the reinforcement structure 100 .

[0314] The capping layer 80 forms a passivation layer.

[0315] All other embodiments of the micromechanical beam 1 , 600 , 650 according to the present disclosure may also include a cover layer 80 .

[0316] The fundamental benchmarks of the micromechanical beam 1, 600 according to the present disclosure are as follows: (i) substantial size reduction—scalability; (ii) routine atomic resolution; (iii) exceptional ease of use; (iv) high operating speed due to high bandwidth; and (v) superior performance in any environment. In summary, the micromechanical beam 1, 600 configured as an active probe featuring the drive structure 70 is more likely to play a role in all future scanning probe technology developments than passive probes using optical readouts. Instead of having to move a bulky sample stage, a more dynamic measurement head including the micromechanical beam 1, 600 must simply be moved across the sample. This radically simplifies the AFM architecture, which can be rearranged in a space-saving manner.

[0317] Reference Signs List

[0318] 1 Micromechanical beam

[0319] 3. Vertical orientation

[0320] 4 Width direction

[0321] 5 Height direction

[0322] 7 Probe structure

[0323] 10 Length

[0324] 11 width

[0325] 12 Height

[0326] 20 fixed end

[0327] 22 free end

[0328] 25 probe segments

[0329] 30 curved sections

[0330] 31 Length of the curved section

[0331] 32 width

[0332] 34 incisions

[0333] 35 minimum lateral width

[0334] 36 maximum lateral width

[0335] 37 length

[0336] 38 openings

[0337] 39 length

[0338] 40 Strengthening Section

[0339] 41 Length of the reinforcement section

[0340] 49 distance

[0341] 50 base elements

[0342] 51 height

[0343] 52 Surface

[0344] 53 Another Surface

[0345] 54 Edge

[0346] 56 maximum width

[0347] 57 minimum width

[0348] 58 marginal areas

[0349] 70 drive structure

[0350] 72 first metal layer

[0351] 73 Height of insulation layer

[0352] 74 second metal layer

[0353] 75 drive structure height

[0354] 76 leads

[0355] 78 insulation layer

[0356] 79 top surface

[0357] 80 Covering Layer

[0358] 90 readout structure

[0359] 92 vertical length

[0360] 94 openings

[0361] 96 readout area

[0362] 97 reinforcement elements

[0363] 98 height

[0364] 99 width

[0365] 100 Strengthened Structure

[0366] 101 Length

[0367] 102 Height

[0368] 104 width

[0369] 107 longitudinal end

[0370] 108 First End

[0371] 109 Second End

[0372] 110 spine

[0373] 111 height

[0374] 112 width

[0375] 120 gap

[0376] 122 width

[0377] 150 Another reinforcement structure

[0378] 171 First Contact

[0379] 172 second contact

[0380] 173 Third Contact

[0381] 174 Fourth Contact

[0382] 175 first resistor

[0383] 176 Second resistor

[0384] 177 Third resistor

[0385] 178 fourth resistor

[0386] 180 stress

[0387] 200 micro-mechanical beams

[0388] 201 support structure

[0389] 401 deflection

[0390] 402 output voltage

[0391] 405 Time

[0392] 500 first precursor structure

[0393] 501 base material

[0394] 502 insulation layer

[0395] 503 beam layer

[0396] 505 another insulation layer

[0397] 510 probe mask

[0398] 515 protective layer

[0399] 520 Second Precursor Structure

[0400] 525 Third Precursor Structure

[0401] 530 Fourth Precursor Structure

[0402] 532 metal layers

[0403] 535 Fifth Precursor Structure

[0404] 536 Sixth Precursor Structure

[0405] 537 Seventh Precursor Structure

[0406] 600 micro-mechanical beam

[0407] 650 micro-mechanical beam

[0408] 700 micro-mechanical beams.< / z>

Claims

1. A micromechanical beam (1, 600, 650, 700) for use in scanning probe measurement, photolithography, etc., the micromechanical beam (1, 600, 650, 700) extending in a longitudinal direction (3) between a fixed end (20) and a free end (22), wherein the beam (1, 600, 650, 700) has a height (12) along a height direction (5) perpendicular to the longitudinal direction (3), the height (12) being smaller than a width (11) along a width direction (4), wherein the beam (1, 600, 650, 700) has a curved section (30) positioned at the fixed end (20) of the beam (1, 600, 650, 700) in the longitudinal direction (3), wherein the beam (1, 600, 650, 700) has a reinforcement section (40) positioned between the curved section (30) and the free end (22) in the longitudinal direction (3), wherein the beam (1, 600, 650, 700) has a base element (50) and a reinforcement structure (100) positioned on the base element (50) in the reinforcement section (40), The reinforcement structure (100) is configured to increase the bending stiffness of the beam (1, 600, 650, 700) in the reinforcement section (40) for bending in the height direction (5).

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

3. The micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the cross-section of the base element (50) and the reinforcing structure (100) in a plane perpendicular to the longitudinal direction (3) has a second moment of section for bending around an axis parallel to the width direction (4), and the second moment of section is greater than the second moment of section of a rectangle having the same width as the base element (50) and the same area as the cross-section of the base element (50) and the reinforcing structure (100) in the plane perpendicular to the longitudinal direction (3), such as at least 5 times, at least 10 times, at least 12 times or at least 13 times.

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

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

6. The micromechanical beam (1, 600, 650, 700) according to claim 5, wherein 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, such as at least 0.2 or at least 0.25, in, 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, Wherein, for example, the aspect ratio is greater than 2.

5.

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

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

9. The micromechanical beam (1, 600, 650, 700) according to claim 8, 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 at least one of claims 8 and 9, Adjacent ridges (110) of the reinforcing structure (100) are connected to each other at alternating longitudinal ends (107) to form a zigzag structure.

11. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the reinforcing structure (100) is a continuous structure extending continuously from a first end (108) to a second end (109) in a plane perpendicular to the height direction (5), in, For example, the first end (108) and / or the second end (109) are positioned at the end of the reinforcement section (40) facing the fixed end (20) of the micromechanical beam (1, 600, 650, 700), Wherein, for example, the first end (108) and the second end (109) are positioned at the same end of the reinforcement section (40).

12. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the reinforcement structure (100) forms part of the conductive structure (70) or forms a support for the conductive structure (70), in, For example, the conductive structure (70) provides a continuous path for electrical current to flow.

13. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, include: Patterned multilayer structures, wherein the patterned multilayer structure comprises the reinforcement structure (100), Therein, for example, the patterned multilayer structure is homogeneously patterned in the height direction (5).

14. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, The reinforcing structure (100) and the base element (50) are made of homogeneous material and are integrally connected together.

15. The micromechanical beam (1, 600, 650, 700) according to at least one of claims 1 to 13, wherein the reinforcement structure (100) comprises a material different from the base material of the base element (50), in, For example, the reinforcement structure (100) is made entirely of a material different from the base material of the base element (50).

16. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the micromechanical beam (1, 600, 650, 700) comprises a conductive metal structure (70) located on top of the reinforcement structure (100), the conductive metal structure being electrically isolated from the reinforcement structure (100), or The reinforcement structure (100) includes the conductive metal structure (70), for example, consists of the conductive metal structure (70).

17. The micromechanical beam (1, 600, 650, 700) according to claim 16, The metal structure (70) has two leads (76) extending longitudinally through the curved section (30) for connection to a power source.

18. The micromechanical beam (1, 600, 650, 700) according to at least one of claims 16 and 17, The metal structure (70) has at least two conductive layers (72, 74) stacked on top of each other in the height direction (5), the conductive layers forming a thermally active multi-metal structure (70) configured to induce bending strain on the beam (1, 600, 650).

19. The micromechanical beam (1, 600, 650, 700) according to at least one of claims 16 to 18, wherein the reinforcement structure (100) has been formed by etching the base member (50) using the metal structure (70) as an etching mask.

20. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the beam (1, 600, 650, 700) has another reinforcement structure (150) positioned within the reinforcement section (40) and placed at another surface (53) of the base element (50) of the beam (1, 600, 650, 700), The surface (52) and the other surface (53) are parallel to each other and are positioned at opposite sides of the base member (50) in the height direction (5).

21. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the beam (1, 600, 650, 700) has a readout structure (90) for measuring the mechanical oscillation of the beam (1, 600, 650, 700) in the height direction (5), such as a piezoresistive readout structure (90) and / or a Wheatstone bridge, The readout structure (90) is positioned in the curved section (30) of the beam (1, 600, 650, 700).

22. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, The beam (1, 600, 650, 700) has at least one lateral cutout (34) positioned in the curved section (30).

23. The micromechanical beam (1, 600, 650, 700) according to claim 22, wherein the beam (1, 600, 650, 700) has two lateral cutouts (34) positioned at opposite side surfaces of the beam (1, 600, 650, 700) in the width direction (4) in the curved section (30), wherein the lateral cutouts (34) narrow the width of the beam (1, 600, 650, 700) to at most 0.85 times, such as at most 0.8 times, at most 0.75 times, at most 0.7 times, or at most 0.67 times, the maximum lateral width (36) of the beam (1, 600, 650, 700) in the curved section (30).

24. Micromechanical beam (1, 600, 650, 700) according to at least claims 21 and 23, in, Over a longitudinal length (37) at least equal to the longitudinal length (92) of the readout structure (90), the width of the beam (1, 600, 650, 700) within the cutout (34) deviates from the minimum lateral width (35) by less than 20%, such as less than 10% or less than 5% or less than 1%.

25. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, wherein the beam (1, 600, 650, 700) comprises a drive structure (70) configured to excite mechanical oscillations of the beam (1, 600, 650, 700) in the height direction (5), The drive structure (70) is positioned within the reinforcement section (40).

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

27. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, The beam (1, 600, 650, 700) comprises at least one longitudinal slot (38) extending over the length (31) of the curved section (30).

28. Micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, in, In the reinforcement section (40), the beam (1, 600, 650, 700) tapers along the longitudinal direction (3) in the width direction (4) by at least 0.1 times, such as at least 0.2 times or at least 0.25 times.

29. Method (200) for producing a micromechanical beam (1, 600, 650, 700) according to at least one of the preceding claims, The method (200) comprises: - providing (205) a base material for the beam (1, 600, 650, 700); - producing (210) a reinforcement structure (100) on a surface (52) of the base material perpendicular to the height direction (5); - manufacturing (220) the individual beams (1, 600, 650, 700) from said base material, wherein the beam (1, 600, 650, 700) extends along a longitudinal direction (3) between a fixed end (20) and a free end (22), wherein the beam (1, 600, 650, 700) has a height (12) along a height direction (5) perpendicular to the longitudinal direction (3), the height (12) being smaller than a width (11) along a width direction (4), The beam (1, 600, 650, 700) has a curved section (30) and a reinforcement section (40), wherein the curved section is positioned at the fixed end (20) of the beam (1, 600, 650, 700) in the longitudinal direction (3), and the reinforcement section is positioned between the curved section (30) and the free end (22) in the longitudinal direction (3). wherein the reinforcement structure (100) is positioned within the reinforcement section (40), and The reinforcement structure (100) is configured to increase the bending stiffness of the beam (1, 600, 650, 700) in the reinforcement section (40) for bending in the height direction (5).

30. The method (200) according to claim 29, The manufacturing (210) of the reinforcement structure (100) includes: - providing (212) a metal structure (70) having leads (76) for connecting to a power supply on said surface (52) of said base material; - etching (214) the base material parallel to the height direction (5) using the metal structure (70) as an etching mask.

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