Scanning probe microscopy system

Abstract

Scanning probe microscopy system comprising an optical microscope arranged to measure lateral coordinates of a target of the scanning probe microscopy system. The optical microscope comprises an objective lens having an optical axis and a linear drive arranged to move the objective lens in a stroke direction. The optical microscope further comprises a compliant mechanism, said compliant mechanism comprising an auxiliary body, a lever arranged to be connected to the metrology frame, a first set of springs, a second set of springs, a third set of springs and a fourth set of springs and are provided such that the optical axis and stroke direction are parallel.

Description

[0001] Title: Scanning probe microscopy system

[0002] The invention relates to a scanning probe microscopy system, preferably a scanning probe microscopy system for use in metrology applications.

[0003] Scanning probe microscopy refers to a method of scanning a surface of a sample with a sharp probe tip in order to obtain its properties. Some of these properties may be the topography, mechanical, electrical, magnet, and I or chemical properties of materials at small scales, e.g. nanoscale.

[0004] Atomic Force Microscopy (AFM) is a commonly used scanning probe microscopy method, in which a sharp tip is attached to a flexible cantilever to scan the sample surface. As the tip interacts with the sample, it produces a surface topography image, preferably at a relatively high resolution, providing information about the height variations and surface features. Other examples of scanning probe microscopy methods are Scanning Tunneling Microscopy (STM), which measures the quantum tunneling current between the tip and the sample to image the electronic properties of conducting materials at the atomic scale, and Magnetic Force Microscopy (MFM), which maps the magnetic fields of a sample.

[0005] An important component of a scanning probe microscope is the optical microscope, said optical microscope can be used to facilitate with the positioning and alignment of the scanning probe over the sample surface. Additionally, an optical microscope can be used as an auxiliary tool to locate the region of interest on the sample before performing the high resolution scanning using the scanning probe method. Specifically, the optical microscope may be used to measure lateral coordinates (X,Y) of a target on the surface of a sample. The features of the target are projected by an objective and tube lens onto a camera sensor, e.g. a CMOS. Knowing the sensor pixel size and the magnification factor of the microscope, one can calculate the size and position of the features of the target.

[0006] In practice a target, such as a semiconductor wafer, is scanned in an X-Y plane, said X-Y plane is parallel to the surface of the semiconductor wafer. The scanning motion in the X-Y plane is detected by the optical microscope, and measures the lateral coordinates (X,Y) on the X-Y plane of the features of the target. Typically, the relative position of the features of the target are known beforehand with a high level of precision. Due to the scanning motion in the X-Y plane, or due to the target surface have irregularities, the feature of the target may vary in the Z-direction, a direction perpendicular to the X-Y plane. As a result, refocusing of the microscope is required to obtain an image of the feature with sufficient quality. In order to refocus the optical microscope, a linear stage is used to move the objective of the optical microscope in the Z-direction. A downside of a linear stage is that it may introduce parasitic lateral movement, i.e. a movement in the X-Y plane, which leads to a measurement error.

[0007] Compliant mechanisms have been proposed to reduce the parasitic lateral movement introduced by the linear stage. A common compliant mechanism design has the objective lens of the microscope mounted to an auxiliary body using two leaf springs. The auxiliary body is connected to a frame using two additional leaf springs. All four leaf springs are provided parallel to each other, such that they can bend in the Z- direction. The linear stage is used to actuate the objective lens in the Z- direction while the compliant mechanism limits movement in the X-Y plane. In order to additionally suppress the parasitic movement further, the compliant mechanism is designed using relatively bulky components, in order to facilitate stiffness. A further downside is that such a compliant mechanism still has noticeable parasitic movement.

[0008] The invention aims to counteract the above disadvantages, preferably while retaining the advantages. More specifically, the invention aims to provide for a scanning probe microscopy system that further reduces the presence of parasitic movement, while keeping the overall design relatively compact.

[0009] Therefore, the invention provides scanning probe microscopy system, in particular a scanning probe microscopy system according to claim 1. The scanning probe microscopy system comprises an optical microscope arranged to measure lateral coordinates of a target of the scanning probe microscopy system. The optical microscope comprises an objective lens having an optical axis. Furthermore, the optical microscope comprises a linear drive arranged to move the objective lens in a stroke direction. The optical microscope further comprises a compliant mechanism, said compliant mechanism comprises an auxiliary body, a lever arranged to be connected to a metrology frame, a first set of springs, a second set of springs, a third set of springs and a fourth set of springs. Each spring of the first set of springs is connected on one end to the metrology frame during use and on another end to the auxiliary body. Additionally, each spring of the second set of springs is connected on one end to the objective lens and on another end to the auxiliary body. Furthermore, each spring of the third set of springs is connected on one end to the auxiliary body and on another end to the lever, and each spring of the fourth set of springs is connected on one end to the objective lens and on another end to the lever. Each spring of the first set of springs and second set of springs has a longitudinal direction transverse to the optical axis and each spring of the fourth set of springs has a longitudinal direction parallel to the optical axis such that the optical axis and stroke direction are parallel. The scanning probe microscopy system can comprise a metrology frame. In the context of the invention, a metrology frame can be any frame to which one or more optical components of the optical microscope can be mounted.

[0010] In order to facilitate focusing, or refocusing, of the optical microscope, the objective lens can be moved in a stroke direction. The movement in stroke direction is provided by the linear drive that acts on the objective lens. Preferably, the linear drive is a linear drive that is arranged to provide an accurate movement of the objective lens over a distance in the order of micrometers, e.g. at least 100 um, such as 150um or 200um, in the stroke direction. This should be understood as the total movement, e.g. in the example of 200um this would mean lOOum in both directions around a neutral, unactuated position. Focusing of the optical microscope on the target requires a relative small movement, for example a movement that is less than half the depth of focus of the objective lens. Therefore, the linear drive should be arranged such that it can provide an accurate movement in the stroke direction to focus the objective lens. If the linear drive is not capable of moving the objective lens sufficiently accurate in the stroke direction, the objective lens may be moved too much in stroke direction such that it has difficulty focusing on the target. Therefore, it is preferred that the linear drive has a minimum step size, i.e. the minimum distance it can move the objective, that is less than 5um, such as 2.5um or preferably less than 1.5 um.

[0011] Furthermore, a compliant mechanism is provided to reduce, or suppress parasitic movement caused by the linear drive. Parasitic movement is the unwanted movement. In the context of the invention, parasitic movement is movement of the objective lens that is in any other direction than the stroke direction. For example, if the stroke direction is in the Z-direction, any movement in the X-Y plane is considered to be a parasitic movement. The compliant mechanism comprises a plurality of sets of springs, connecting the objective lens to the auxiliary body and the auxiliary body to metrology frame during use. The sets of springs are provided such that, combined, a movement in the Z-direction is facilitated while the movement in the X-Y plane is suppressed. Preferably, the parasitic movement is suppressed such that the remaining parasitic movement is less than lOOnm, for example less than 75nm or more preferably less than 50nm. Each set of springs may facilitate the movement in a single cardinal direction while limiting movement in the other two cardinal directions. This may for example be done using leaf springs in as each spring in the set of springs.

[0012] When the sets of springs, auxiliary body, lens objective and linear drive are provided as previously disclosed, the optical axis of the objective is parallel to the stroke direction. The objective lens can be moved by the linear drive, however the parasitic movement can be significantly suppressed by the compliant mechanism. Additionally, the above configuration of the compliant mechanism may provide for a relatively compact design without having the linear drive coaxial with the optical axis of the objective lens.

[0013] The lever can comprise a first body and a second body, wherein the first body can be connected on one end to the metrology frame during use and on another end to the second body via a flexure hinge. The flexure hinge can be arranged to allow the first body and second body to hinge around a hinge axis, said hinge axis being transverse to the optical axis. Each spring of the third and fourth set of springs can be connected to the lever on the second body of the lever. Providing a lever that comprises two parts, connected via the flexure hinge, may further suppress parasitic movement provided by the linear drive as it compensates for manufacturing differences that may be introduced when manufacturing the first and second set of springs. When the linear drive moves the objective lens, the first body of the lever does stays in an upright position, while the second body of the lever moves rotates around the high axis provided by the flexure hinge via the fourth set of springs. The fourth set of springs is preferably a leaf spring, facilitating movement in the X-direction, while limiting movement in the Y- and Z-direction. Due to the orientation of the flexure hinge, the rotational movement of the second body has a component in the Z-direction and in the X-direction while suppressing movement in the Y-direction. This rotational movement is transferred to the objective lens via the third set of springs.

[0014] Each spring of the third set of springs can comprise a first section having a longitudinal direction and a second section having a longitudinal direction, wherein the longitudinal direction of the first section can be transverse to the optical axis and the longitudinal direction of the second section can be parallel to the optical axis. Preferably, each section of the third set of springs facilitates the movement in a single cardinal directions while limiting the movement in the two other cardinal directions. For example, each section of the third set of springs may be a leaf spring. In a preferred embodiment, the first section may facilitates movement in the Y- direction while suppressing movement in the X- and Z-direction. The second section may facilitate movement in the X- direction while suppressing movement in the Y- and Z- direction. In combination with the lever, and in particular with the above described lever comprising of two bodies connected via a flexure hinge, movement in the X-Y plane parasitic movement of the linear drive on the optical axis of the objective lens may be further suppressed. Alternatively, each spring of the third set of springs may have a mass as the second section, i.e. relatively heavy component, that is stiff in a direction parallel to the optical axis. The first section than can be a horizontal strut, for example a leaf spring, a rod or a preloaded string with high enough tension that facilitates a very small stiffness in the direction transverse to the optical axis and a relatively high stiffness in the direction parallel to the optical axis.

[0015] The fourth set of springs can be connected to the hinge at a first distance from an end of the hinge. The third set of springs can be connected to the hinge at a second distance from the end of the hinge. Preferably, the fourth set of springs can be connected to the second body of the hinge at a first distance from the flexure hinge and the third set of springs can be connected to the second body at a second distance from the flexure hinge. The second distance can be smaller than the first distance. Preferably, the second distance can be half the first distance. The rigidness provided by the lever, in combination with the third and fourth set of springs, may be used to facilitate further suppressing of the parasitic movement in the X- and Y- direction by connecting the lever to the auxiliary body via a connection provided in the middle of the second body of the lever.

[0016] The objective lens can be connected to the second and fourth set of springs via a main body. The main body can clamp the objective lens, thereby facilitating removal of the objective lens. This may facilitate using the same compliant mechanism for different objective lenses, or the removal or replacement of an objective lens, e.g. when broken or needs to be removed for maintenance.

[0017] The optical microscope can further comprise a fifth set of springs. Each spring of the fifth set of springs can be connected on one end to the linear drive and on another end to the objective lens, preferably via a main body. Each spring of the fifth set of springs can have a longitudinal direction parallel to the optical axis. In a preferred embodiment, the fifth set of springs comprises a leaf spring provided such that a movement in the X- direction is facilitated, while the movement in the Z- and Y- direction is suppressed. This may allow placement of the linear drive at a preferred location, i.e. without being restricted to the location of the objective lens. This may allow for providing the linear drive out of the optical axis while keeping the design compact.

[0018] The third set of springs is connected to the auxiliary body via a bonded contact. Additionally or alternatively, the fourth and fifth set of springs are connected to the main body via bonded contacts and the fourth set of springs are connected to the lever via bonded contacts. Bonded contacts prevent sliding or separation of the corresponding components, e.g. preventing the fourth set of springs from sliding relative to, or being separated from, the lever. Bonded contacts may be provided via welding, or a threaded connection such as screws.

[0019] The first set of springs can comprise two springs provided on opposite ends of the auxiliary body in the stroke direction. Additionally or alternatively, the second set of springs can comprises two springs provided on opposite ends of the objective lens in the stroke direction. This way, first the and I or second set of springs may facilitate support of the objective lens.

[0020] The third set of springs can comprise two springs provided on opposite ends of the objective lens in a direction transverse to the stroke direction.

[0021] At least one spring of the first set, second set, third set, fourth set and fifth set of springs can comprise a leaf spring. However, it will be understood by the person skilled in the art that all sets of springs can comprise other mechanisms than leaf springs as long as the other mechanisms can replicate the same stiffness constrains as the leaf springs.

[0022] Further advantageous aspects of the invention are set out in the description and appended claims.

[0023] The technical features described in the paragraphs and sentences above can be isolated from the context, and the isolated technical features from the different paragraphs and sentences can be combined. Such combinations are herewith specifically disclosed in this description.

[0024] The invention will further be elucidated on the basis of exemplary embodiments which are represented in the drawings. The exemplary embodiments are given by way of non-limitative illustration of the invention.

[0025] In the drawings:

[0026] Fig. 1A and IB show a schematic view of an objective lens and a compliant mechanism according to the state of the art;

[0027] Fig. 2A and 2B show a schematic view of an objective lens and a compliant mechanism according to an example of the invention; Fig. 3 shows an isometric view of a scanning probe microscopy system according to an example of the invention;

[0028] Fig. 4 shows a side view of the scanning probe microscopy system of Fig. 3; and

[0029] Fig. 5 shows an isometric bottom view of an ever further example of a scanning probe microscopy system.

[0030] It is noted that the figures are only schematic representations that are given by way of non-limited examples. In the figures, the same or corresponding parts are designated with the same reference numerals.

[0031] Figs. 1A and IB depict a schematic side view of an objective lens 1 and a compliant mechanism 100 according to the state of the art. Fig. 1A depicts the objective lens 1 and compliant mechanism 100 in a neutral state, i.e. not actuated by a linear drive (not depicted), while Fig. IB depicts the objective lens 1 and compliant mechanism 100 in a perturbed state, in which a linear drive (not depicted) moved the objective lens 1 in a Z-direction. In particular, an optical axis 2 of the objective lens 1 is translated in the Z- direction to, for example, to refocus the image of the target. In order to suppress parasitic lateral movement in a X-Y plane, said plane being perpendicular to the Z-direction, the compliant mechanism 100 is provided. The mechanism 100 comprises an auxiliary body 101, said auxiliary body 101 is attached to a fixed object 102, for example a metrology frame 102, via two leaf springs 103 during use. The leaf springs 103 are provided such that their lowest bending resistance is in the Z-direction, i.e. e.g. by having their smallest dimension in the Z-direction. Additionally, leaf springs 103 are provided in the X-Y plane, and spaced apart in the Z-direction such that the objective lens 1 and further leaf springs 104 can be provided in the space between the leaf springs 103.

[0032] The objective lens 1 is connected to the auxiliary body 101 via two further leaf springs 104. Said further leaf springs 104 are provided in the X- Y plane, and spaced apart in the Z-direction such that the objective lens 1 can be provided in the space between the further leaf springs 104. Additionally, the further leaf springs 104 are provided such that their lowest bending resistance is in the Z-direction, e.g. by having their smallest dimension in the Z-direction.

[0033] Objective lens 1 is only attached to the fixed object 102 via the leaf springs 103, 104 and the auxiliary body 101 and via the non-depicted linear drive. Due to the layout of the leaf springs 103, 104 movement of the objective lens 1 is suppressed in the X-Y plane due to the relatively high bending resistance provided by said leaf springs 103, 104 in the X- and Y- direction while it is facilitated in the Z-direction. In order to translate the objective lens 1, and thereby the optical axis 2 in the Z-direction, a force F can be applied directly on the objective lens 1 by a linear drive. While such a compliant mechanism 100 suppresses some parasitic movement in the X-Y plane caused by the linear drive, the remaining parasitic movement may still cause too much of a measurement error in practice.

[0034] Turning to Figs. 2A and 2B a schematic side view of an objective lens 1 and a compliant mechanism 10 according to an example of the invention has been depicted. Fig. 2A depicts the objective lens 1, having an optical axis 2, and compliant mechanism 10 in a neutral state, i.e. not actuated by a linear drive 28, while Fig. 2B depicts the objective lens 1 and compliant mechanism 10 in a perturbed state, in which the linear drive 28 actuated the objective lens 1 in a stroke direction. In particular, an optical axis 2 of the objective lens 1 is translated in the stroke direction, or Z- direction, in order to refocus an image.

[0035] Compliant mechanism 10 is provided in order to suppress parasitic lateral movement in a X-Y plane, said plane being perpendicular to the Z-direction. The mechanism 10 comprises an auxiliary body 11, said auxiliary body 11 is attached to a fixed object 12, for example a metrology frame 12, via two leaf springs 13 during use. The two leaf springs 13 make up the first set of springs. Each spring of the first set of leaf springs 13 is connected on one end to the metrology frame 12 during use and on another end to the auxiliary body 11. The leaf springs 13 are provided such that their lowest bending resistance is in the Z-direction, e.g. by having their smallest dimension in the Z-direction. The leaf springs 13 are provided parallel to each other in the X-Y plane, i.e. each spring of the first set of springs 13 has a longitudinal direction transverse to the optical axis 2, and spaced apart in the Z-direction such that the objective lens 1 and further leaf springs 14 can be provided in the space between the leaf springs 13.

[0036] The objective lens 1 is connected to the auxiliary body 11 via two further leaf springs 14, said two further leaf springs 14 making up the second set of springs. Each spring 14 of the second set of springs is connected on one end to the objective lens 1 and on another end to the auxiliary body 11. Said further leaf springs 14 are provided parallel to each other in the X-Y plane, i.e. each spring of the second set of springs 13 has a longitudinal direction transverse to the optical axis 2, and spaced apart in the Z-direction such that the objective lens 1 can be provided in the space between the further leaf springs 14. Additionally, the further leaf springs 14 are provided such that their lowest bending resistance is in the Z-direction, e.g. by having their smallest dimension in the Z-direction.

[0037] Additionally, a lever 15 is provided that is connected to the metrology frame 12 during use. In the shown example, the lever 15 comprises a first body 16 and a second body 17, wherein the first body 16 is connected on one end to the metrology frame 12 during use and on another end to the second body 17 by a flexure hinge 18. The flexure hinge 18 is arranged to allow the first body 16 and the second body 17 to hinge around a hinge axis 19. In the shown example, the hinge axis 19 is transverse to the optical axis 2. The second body 18 is connected to the auxiliary body 11 via a third set of springs.

[0038] In the shown example, the third set of springs comprises two L- shaped leaf springs 20, each provided on a side of the compliant mechanism 10. Each spring of the third set of springs is connected on one end to the auxiliary body 11 and on another end to the lever 15, or in the shown example to the second body 17 of the lever 15. The L-shaped leaf springs 20 each comprises two sections, a first section 21 and a second section 22, both sections 21, 22 having a longitudinal direction. The longitudinal direction of the first section 21 is transverse to the optical axis 2, the longitudinal direction of the second section 22 is parallel to the optical axis 2. As a result, the longitudinal direction of the first section 21 is at a 90 degree angle with the longitudinal direction of the second section 22, thereby forming an L- shape. The first section 21 has a bending resistance that’s smallest in Y- direction, the second section 22 has a bending resistance that’s smallest in X-direction.

[0039] A fourth set of springs is provided, the fourth set of springs in the depicted example of the invention being a single leaf spring 23. The leaf spring 23 is connected between the first second body 17 of the lever 15 and the objective lens 1. The leaf spring 23 is connected on one end to the objective lens 1 and on another end to the lever 15. The leaf spring 23 has a longitudinal direction, and the leaf spring 23 is provided such that its longitudinal direction is parallel to the direction of the optical axis 2. The single leaf spring 23 has a bending stiffness that is smallest in X-direction.

[0040] Leaf spring 23, or the fourth set of springs, is connected to the second body 17 of the lever 15 at a first distance DI from the flexure hinge 19. The third set of springs, or the pair of L-shaped leaf springs 20, is provided at a second distance D2 from the flexure hinge 19. In the shown example, the distance D2 is half the distance DI.

[0041] In the shown example, the objective lens 1 is connected to the second and fourth set of springs via a main body 24. The main body 24 clamps the objective lens 1.

[0042] On an opposite side of the main body 24, a fifth set of springs is provided. The fifth set of springs has a single leaf spring 25 that forms a connection between the linear drive 28 and the main body 24. The leaf spring 25 is connected on one end to the linear drive 28 and on another end to the objective lens 1 via the main body 25. The leaf spring 25 has a longitudinal direction that is parallel to the optical axis 2.

[0043] Turning to Fig. 3 an isometric view of an example of an optical microscope arranged to measure lateral coordinates of a target of a scanning probe microscopy system is shown. The optical microscope comprises an objective lens 1 having an optical axis 2. A linear drive (not depicted) can be used to move the objective lens 1 in a stroke direction that is parallel to the optical axis 2. The compliant mechanism 10 is provided to reduce, or eliminate, any parasitic movement introduced by the linear drive when moving the objective lens 1 in the stroke direction. In the shown example, the linear drive can move the objective lens 1 in the stroke direction by applying a force F to the single leaf spring 25 of the fifth set of springs. The single leaf spring 25 is provided on the bottom side of the compliant mechanism 10 and is connected to the main body 24 as can be seen in Fig 5. Main body 24 is connected to the second body 17 of the lever 15 via leaf spring 23 of the fourth set of springs. This way, when force F is applied to single leaf spring 25, second body 17 of the lever 15 will be acted upon. Second body 17 can hinge around hinge axis 19 provided by the flexure hinge 18, said flexure hinge 18 forming an elastic deformable connection between the second body 17 and the first body 16. First body 16, as well as each of the leaf springs 13 of the first set of springs, can be connected to the metrology frame (not depicted) via base part 26. When the second body 17 rotates about hinge axis 19, the L-shaped leaf springs 20 of the third set of springs causes main body 24 to move in the stroke direction. As a result, the objective lens 1 which is attached to main body 24 via a clamping mechanism, can move in the stroke direction, through the opening 27 provided in the first and second body of the hinge 15. Many variations will be apparent to the skilled person in the art.

[0044] Such variations are understood to be comprised within the scope of the invention as defined in the appended claims.

Claims

Claims1. Scanning probe microscopy system comprising: an optical microscope arranged to measure lateral coordinates of a target of the scanning probe microscopy system; wherein the optical microscope comprises an objective lens having an optical axis; wherein the optical microscope further comprises a linear drive arranged to move the objective lens in a stroke direction; wherein the optical microscope further comprises a compliant mechanism, said compliant mechanism comprising an auxiliary body, a lever arranged to be connected to a metrology frame, a first set of springs, a second set of springs, a third set of springs and a fourth set of springs; wherein: each spring of the first set of springs is connected on one end to the metrology frame during use and on another end to the auxiliary body; each spring of the second set of springs is connected on one end to the objective lens and on another end to the auxiliary body, each spring of the third set of springs is connected on one end to the auxiliary body and on another end to the lever, each spring of the fourth set of springs is connected on one end to the objective lens and on another end to the lever, and wherein each spring of the first set of springs and second set of springs has a longitudinal direction transverse to the optical axis; wherein each spring of the fourth set of springs has a longitudinal direction parallel to the optical axis; such that the optical axis and stroke direction are parallel.

2. Scanning probe microscopy system according to claim 1, wherein the lever comprises a first body and a second body,wherein the first body is connected on one end to the metrology frame during use and on another end to the second body via a flexure hinge, the flexure hinge is arranged to allow the first body and second body to hinge around a hinge axis, said hinge axis being transverse to the optical axis, and wherein each spring of the third and fourth set of springs are connected to the lever on the second body of the lever.

3. Scanning probe microscopy system according to claim 1 or 2, wherein the objective lens is connected to the second and fourth set of springs via a main body, wherein the main body clamps the objective lens.

4. Scanning probe microscopy system according to any of the preceding claims, wherein the optical microscope further comprises a fifth set of springs, wherein each spring of the fifth set of springs is connected on one end to the linear drive and on another end to the objective lens, preferably via a main body, and wherein each spring of the fifth set of springs has a longitudinal direction parallel to the optical axis.

5. Scanning probe microscopy system according to any of the preceding claims, wherein each spring of the third set of springs comprises a first section having a longitudinal direction and a second section having a longitudinal direction, wherein the longitudinal direction of the first section is transverse to the optical axis and the longitudinal direction of the second section is parallel to the optical axis.

6. Scanning probe microscopy system according to any of the preceding claims, wherein the fourth set of springs is connected to the hinge at a first distance from an end of the hinge, and wherein the third set of springs is connected to the hinge at a second distance from the end of the hinge.

7. Scanning probe microscopy system according to claim 6, wherein the second distance is smaller than the first distance.

8. Scanning probe microscopy system according to claim 6, wherein the second distance is half the first distance.

9. Scanning probe microscopy system according to any of the preceding claims, wherein the third set of springs is connected to the auxiliary body via a bonded contact.

10. Scanning probe microscopy system according to any of the preceding claims, wherein the first set of springs comprises two springs provided on opposite ends of the auxiliary body in the stroke direction.

11. Scanning probe microscopy system according to any of the preceding claims, wherein the second set of springs comprises two springs provided on opposite ends of the objective lens in the stroke direction.

12. Scanning probe microscopy system according to any of the preceding claims, wherein the third set of springs comprises two springs provided on opposite ends of the objective lens in a direction transverse to the stroke direction.

13. Scanning probe microscopy system according to any of the preceding claims, wherein at least one spring of the first set, second set, third set, fourth set and fifth set of springs comprises a leaf spring.

14. Scanning probe microscopy system according to any of the preceding claims further comprising a metrology frame.

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