Supporting substrate for nanostructures

Abstract

A support substrate (1) for nanostructures (2), particularly carbon nanotubes, is provided, the support substrate (1) comprising a plurality of cantilever pairs (13), each configured to hold a nanostructure (2) therebetween. At least some of the plurality of cantilever pairs (13) are arranged to extend in different, non-parallel directions along at least a curved or angled portion of the periphery (11) of the support substrate (1). An apparatus (4) is also provided for attaching nanostructures (2) to a device substrate (3) using such a support substrate (1), and a method is also provided for attaching nanostructures (2) to a device substrate (3) using such a support substrate (1).

Description

[Technical Field]

[0001] The present invention relates to a support substrate for nanostructures, particularly for carbon nanotubes. The support substrate serves to support the nanostructures and to attach the nanostructures to a device substrate. The present invention also relates to an apparatus for attaching nanostructures to a device substrate using such a support substrate, and to a method for attaching nanostructures to a device substrate using such a support substrate. [Background technology]

[0002] Nanostructures are increasingly being applied in nanoelectromechanical devices for many different applications. Particularly with respect to semiconductor devices, nanostructures are expected to play an important role in the future. Transistors and simple electronic circuits have already been successfully fabricated with semiconducting and metallic carbon nanotubes.

[0003] A particular challenge in fabricating devices with nanostructures is the growth of individual nanostructures that are isolated from one another, as opposed to grouped together, and the precise transfer and attachment of the nanostructures from the growth substrate to the target device. In the prior art, random or parallel deposition of nanotubes or the like onto a device substrate with multiple devices is typically applied. However, random deposition requires that most of the devices be discarded because no nanostructures are deposited, excessive nanostructures are deposited, or the nanostructures are not precisely positioned on the device. As a result, the device yield when using such random deposition procedures is relatively low.

[0004] Growth of suspended or freestanding nanostructures, such as carbon nanotubes between cantilevers, has recently been developed to overcome these problems associated with random deposition. By suspending nanostructures between pairs of cantilevers, the carbon nanotubes can be engineered away from any device to which they will subsequently be applied. In this manner, nanostructures can be fabricated in an optimal environment with minimal charge noise, such as from semiconductor device interfaces. Growing or depositing suspended nanostructures between horizontal cantilevers also allows for preselection of the nanostructures to be used using optical methods, such as laser techniques. Using such preselection, the quality of the nanostructures to be used can be verified using nondestructive optical methods (e.g., Raman spectroscopy). Therefore, the growth substrate can be brought close to the device substrate for transferring the preselected nanostructures to the device in which they will be used.

[0005] The growth of suspended nanostructures in the form of carbon nanotubes between cantilevers and the subsequent transfer of the nanotubes to nanoelectromechanical devices has been demonstrated, for example, in [1].

[0006] In Non-Patent Document 2, the fabrication of carbon nanotube field effect transistors is disclosed using a growth substrate with a cantilever structure.

[0007] Another prior art document that discloses the fabrication of a device using nanostructures held between two cantilevers of a growth substrate is [3].

[0008] Further publications disclosing the practice of growing nanostructures between horizontally extending cantilevers and subsequently transferring them to a device substrate are, for example, "Nanostructure Growth between Horizontally Extended Cantilevers and Their Subsequent Transfer to a Device Substrate," in J. Appl. Phys.

[0009] The aforementioned prior art methods for growing and transferring nanostructures to target devices have the disadvantage of limited scalability. For industrial production of large numbers of identical or similar devices, previously known prior art methods have been limited in efficiency, i.e., speed of production. Furthermore, process control is limited, which inevitably results in a large number of discarded devices. Therefore, producing devices with nanostructures using typical prior art methods is not very cost-effective. However, it is expected that, for example, next-generation sensors, computer chips, and quantum processors will increasingly be used in the future. The ability to industrially mass-produce such sensors, computer chips, and quantum processors containing nanostructures will be a key factor for the widespread application of this technology in many different electrical appliances. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] T. Cubaynes, LC Contamin, MC Dartiailh, MM Desjardins, A. Cottet, MR Delbecq, T. Kontos, Nanoassembly technique of carbon nanotubes for hybrid circuit-QED, Appl. Phys. Lett. 117 (2020) 114001 [Non-patent document 2] M. Muoth, C. Hierold, Transfer of carbon nanotubes onto microactuators for hysteresis-free transistors at low thermal budget, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE (2012) 1352-1355 [Non-patent document 3] V. Ranjan, G. Puebla-Hellmann, M. Jung, T. Hasler, A. Nunnenkamp, ​​M. Muoth, C. Hierold, A. Wallraff, C. Schonenberger, Clean carbon nanotubes coupled to superconducting impedance-matching circuits, Nature Communications 6 (2015) 7165 [Non-patent document 4] S. Blien, P. Steger, A. Albang, N. Paradiso, AK Huttel, Quartz Tuning-Fork Based Carbon Nanotube Transfer into Quantum Device Geometries, Phys. Status Solidi B. 255 (2018) 1800118 Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a support substrate for the production of nanostructures, in particular the production of carbon nanotubes, that allows for a particularly efficient and therefore cost-effective fabrication of devices involving nanostructures. [Means for solving the problem]

[0012] This object is solved by a support substrate as claimed in claim 1. An apparatus for attaching nanostructures to a device substrate using such a support substrate is claimed in claim 9. Claim 14 provides a method for attaching such nanostructures to a device substrate. Further embodiments are provided in the dependent claims.

[0013] The present invention therefore provides a support substrate for nanostructures, in particular carbon nanotubes or graphene, comprising a plurality of cantilever pairs each configured to hold a nanostructure therebetween, at least some of the plurality of cantilever pairs being arranged to extend in different, non-parallel directions along at least a curved or angled portion of the periphery of the support substrate.

[0014] By having multiple cantilever pairs arranged along at least a curved or angled portion of the periphery of the support substrate so that the cantilever pairs extend in different, non-parallel directions, the support substrate can accommodate a significantly larger number of cantilever beams, and therefore a significantly larger number of nanostructures, supported thereon. Furthermore, and more importantly, when the cantilever pairs extend in different, non-parallel directions, mechanical collisions between the support substrate and adjacent devices can be avoided to a significant extent, making the support substrate scalable in terms of the size and number of cantilever pairs. In prior art, the cantilevers are typically all arranged parallel on one side of a rectangular support substrate, which poses a problem of potential collisions between the cantilevers and adjacent devices when the nanostructures are transferred to the devices. Because the devices are typically uniformly spaced in adjacent rows on a device substrate in the form of a wafer or pallet, if the support substrate were to be extended to accommodate a larger number of cantilever pairs that all extend parallel, the parallel-extending cantilever pairs could easily collide with adjacent devices. Therefore, typical prior art production processes have very limited scalability. In contrast, with the approach according to the present invention, in which cantilever pairs are arranged along at least a curved or angled portion of the periphery of the support substrate so that they extend in different, non-parallel directions, the provision of more support substrates with a greater number of cantilevers results in no collisions, or collisions to a much lesser extent. Therefore, the production process for devices involving nanostructures becomes scalable, thereby enabling more efficient and therefore more cost-effective production of devices.

[0015] Thus, by disposing cantilever pairs along at least a curved or angled portion of the periphery of the support substrate, and preferably along the entire periphery, the number of cantilever pairs can be significantly increased. In preferred embodiments, the support substrate has more than 1,000 cantilever pairs, more preferably more than 3,000 cantilever pairs, and most preferably more than 5,000 cantilever pairs. By comparison, prior art rectangular support substrates with cantilevers along only one edge of the substrate typically have only 50 to 100 cantilever pairs.

[0016] In a preferred embodiment, the support substrate not only serves to support the nanostructures but also to grow them. The support structure, in this case, can also be referred to as a growth structure that serves to fabricate the nanostructures. Growth of the nanostructures between the cantilever pairs on the support substrate can be initiated by providing an appropriate catalyst at each location on the support structure. In other embodiments, the nanostructures are not grown on the support substrate, but are dispersed in a solution, and the nanostructures are transferred or "fished" from the solution to the support substrate by immersing the cantilever pairs on the support structure into the solution. In yet other embodiments, the nanostructures are not grown on the support structure, but are deposited onto the cantilever pairs, for example by spraying.

[0017] Nanostructures are considered to be structures intermediate in size between microstructures and molecular structures. Nanostructures include structures in the nanometer (typically 1-100 nm) range. Nanostructures can have elongated shapes and can be in the form of nanotubes or nanowires. However, nanostructures can also have shapes that extend in two dimensions and can be in the form of graphene variants, transition metal dichalcogenide layers, or boron nitride nanosheets. Nanostructures can be suspended or free-standing.

[0018] Nanotubes, especially carbon nanotubes, have two dimensions on the nanoscale, i.e. the diameter of the tube is between 0.1 nm and 100 nm, however the length of the nanotubes can be much greater.

[0019] The cantilevers preferably all extend outward from the periphery of the main portion of the support substrate. The extension of each cantilever is preferably along a horizontal direction, i.e., perpendicular to the direction of gravity. Therefore, each cantilever preferably has a design in the form of an elongated rod or pole with its free end pointing away from the main portion of the support substrate. Advantageously, each cantilever pair comprises two cantilevers extending parallel to each other. Therefore, one or more nanostructures are typically grown vertically between the two cantilevers. Therefore, the cantilever pair is not only configured to hold the nanostructures between them, but is also preferably configured to grow the nanostructures between them. In other embodiments, the nanostructures are grown elsewhere before being deposited on the cantilever pair. The nanostructures are preferably attached to the target device by lowering the support substrate onto the device substrate, preferably so that the nanostructures are located at the target positions of the device. Therefore, for the transfer of the nanostructures to the target device, the device, or at least a portion thereof, is preferably positioned between the cantilevers.

[0020] In particularly preferred embodiments, the plurality of cantilever pairs are distributed along the entire periphery of the support substrate. For a circular support substrate, this means that the portions of the periphery without cantilever pairs each span an arc of less than 90°, preferably less than 60°, more preferably less than 45°, and most preferably less than 30°. For a polygonal support substrate, distribution of the plurality of cantilever pairs along the entire periphery means that each edge formed by the polygon comprises at least one cantilever pair.

[0021] Each of the cantilever pairs preferably extends outwardly along an approximate radial direction of the support substrate, where approximate radial direction is understood to be a direction that deviates from the exact radial direction by preferably less than 45°, more preferably less than 20°, and most preferably less than 5°.

[0022] The periphery of the support substrate preferably describes the overall shape of a circle or a regular polygon. These regular shaped overall shapes of the support substrate are particularly well configured with regard to scalability.

[0023] The cantilever pairs may be evenly distributed along the entire periphery of the support substrate, but this is not necessarily the case. Alternatively, the cantilever pairs may be arranged in groups of cantilever pairs extending parallel to one another. Therefore, the distance between the cantilever pairs within each group is typically different and preferably an integer multiple smaller than the distance between the two groups. Alternatively or additionally, the groups may deviate from one another in the direction along which the cantilever pairs extend. Preferably, any two adjacent groups of cantilever pairs extending parallel to one another are at an angle of 10° or less, preferably 8° or less, and more preferably 6° or less relative to one another. Within each group, the cantilever pairs preferably extend parallel. However, the cantilever pairs of different groups can extend along different directions. Arranging the cantilever pairs in groups offers the advantage that the support substrate can be optimally configured for transfer of nanostructures to a device substrate, where devices are typically uniformly spaced apart in adjacent rows.

[0024] Within each group, the cantilever pairs are preferably evenly spaced apart. The groups are preferably evenly distributed, i.e., at regular distances, advantageously distributed along the entire periphery of the support substrate. The groups are in particular arranged along a circular periphery formed by the main part of the support substrate. In the region of each group, the support substrate may have a radially extending portion extending radially outward from the main part of the support substrate, so that the cantilevers extend outward from the radially extending portion. A radially extending portion may therefore be associated with each group of the plurality of cantilever pairs.

[0025] Each group of the plurality of cantilever pairs preferably extends outwardly along an approximate radial direction of the support substrate, more preferably along a radial direction, where approximate radial direction is understood to be a direction that deviates from the exact radial direction by preferably less than 45°, more preferably less than 20°, and most preferably less than 5°.

[0026] The support substrate can be, but is not necessarily, made as a single piece. Thus, in certain embodiments, the cantilever pairs can be made as a single piece with the main portion of the support substrate. However, in other embodiments, the cantilever pairs, and in particular the radially extending portions comprising the cantilever pairs, can be attached to the main portion of the support substrate so that they are not made as a single piece, e.g., from a different material than the main portion. For example, the main portion of the support substrate can be in the form of a circular or polygonal plate to which multiple radially extending portions comprising the cantilever pairs are attached along its periphery. In this case, the radially extending portions comprising the cantilever pairs, together with the main portion, form the support substrate. Thus, the support substrate of the present invention can be provided in a particularly easy manner, for example, by attaching multiple leading edge support substrates, each having a rectangle with only one side along which the cantilever pairs are arranged parallel, to the periphery of a circular or rectangular plate.

[0027] Preferably, the support substrate has a generally planar shape. Therefore, the extension of the support substrate along two perpendicular spatial directions is preferably at least two orders of magnitude, more preferably at least three orders of magnitude, greater than along a third perpendicular spatial direction. The cantilever pairs preferably extend in a common plane. Therefore, preferably, the extension of all cantilevers lies in the same plane, more preferably in the same plane as the main portion of the support substrate.

[0028] Preferably, the device substrate has an overall planar shape. Therefore, the extension of the device substrate along two perpendicular spatial directions is preferably at least two orders of magnitude, more preferably at least three orders of magnitude, greater than along the third perpendicular spatial direction. The device to which the nanostructures are attached is in each case formed by the device substrate. The device substrate may comprise only a single device. Preferably, however, the device substrate comprises a plurality of devices, in particular a plurality of nanoelectromechanical devices. Nanoelectromechanical devices are electromechanical devices having functional components with dimensions in the nanometer range. The devices may in particular be semiconductor devices.

[0029] The present invention provides an apparatus for attaching nanostructures, particularly carbon nanotubes, to a device substrate, comprising: a holder for holding the support substrate as described above, the holder including a plurality of cantilever pairs extending in different non-parallel directions within a common plane; and a positioner for positioning the device substrate, onto which one or more of the nanostructures are attached, relative to the support substrate.

[0030] The apparatus is configured to move the holder and positioner relative to each other so that nanostructures, each held between a pair of cantilevers, are transferred from the support substrate to multiple attachment points on the device substrate for attachment to the device substrate.

[0031] The apparatus is configured to rotate the support substrate about an axis of rotation extending perpendicularly through a common plane of the plurality of cantilever pairs to sequentially deposit nanostructures onto the device substrate.

[0032] A particularly simple and efficient fabrication of devices can be achieved by rotating the support substrate to sequentially deposit nanostructures onto the device substrate. As further indicated above, the concept of having a support substrate with a curved or angled perimeter and non-parallel cantilever pairs is directly linked to the concept of rotating the support structure to deposit nanostructures onto the device substrate. Thus, the support substrate and apparatus as indicated above relate to one inventive concept.

[0033] The device is preferably a motorized device, which means that the holder can be moved relative to the positioner by means of a motor, in particular an electric motor.

[0034] The holder refers to a component of the apparatus that allows a support substrate to be attached to the apparatus for transferring nanostructures from the support substrate to the device substrate. The positioner serves to position the device substrate so that the nanostructures can be safely and accurately transferred from the support substrate to the device substrate. Thus, the positioner preferably serves to hold the device substrate in the required position during transfer.

[0035] In a preferred embodiment, the positioner is stationary while the holder is movable, in particular by means of a motor, however, in other embodiments it is also conceivable that the holder is stationary while the positioner is movable, or that both the holder and the positioner are movable.

[0036] In a particularly preferred embodiment, the rotation axis is tilted or tiltable with respect to the geometric normal of the device substrate plane where the attachment points are located. The device substrate plane is therefore defined by the locations of the attachment points. The attachment points are the points at which the nanostructures are attached to the device substrate. When the nanostructures are carbon nanotubes, there are typically two attachment points for each nanostructure. By tilting the rotation axis with respect to the device substrate for the transfer of the nanostructures, collisions of the cantilever with adjacent devices can be particularly well avoided while still ensuring very precise placement of the nanostructures on the device substrate.

[0037] The tilt angle at which the rotation axis is tilted or can be tilted relative to the geometric normal to the device substrate plane is preferably in the range of 1° to 40°, more preferably in the range of 4° to 20°, and particularly preferably in the range of 4° to 10°. Tilt angles in these ranges have proven particularly well suited to avoiding collisions on the one hand and ensuring accurate positioning on the other hand.

[0038] The apparatus is preferably configured to move the support substrate relative to the positioner along an x-direction extending perpendicular to the axis of rotation. The apparatus is further configured to move the support substrate relative to the positioner along a y-direction extending perpendicular to both the x-direction and the axis of rotation. In this manner, nanostructures can be efficiently transferred to multiple devices positioned next to each other.

[0039] The present invention relates in particular to a method for attaching nanostructures, in particular carbon nanotubes, to a device substrate using an apparatus as described above, wherein the nanostructures are each disposed between a pair of cantilevers on a support substrate as described above, the cantilevers extending in different non-parallel directions in a common plane; - to attach the nanostructures to the device substrate, the method further relates to a method comprising at least the step of rotating the support substrate about a rotation axis extending vertically through a common plane to continuously transfer the nanostructures from the support substrate to a plurality of attachment points on the device substrate.

[0040] To attach the nanostructures to the device substrate, the rotation axis is preferably tilted relative to the geometric normal of the device substrate plane in which the attachment points are arranged. In this way, collisions can be avoided.

[0041] Preferred embodiments of the present invention are described below with reference to the drawings, which are not for purposes of limiting the invention but for purposes of illustrating presently preferred embodiments of the invention. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a perspective view of a prior art growth substrate in a starting position for the transfer of nanostructures to two devices disposed on a common device substrate. [Figure 2] FIG. 2 is a perspective view of the growth substrate and device substrate of FIG. 1 during transfer of the nanostructures to the device. [Figure 3] FIG. 2 is a perspective view of the growth substrate and device substrate of FIG. 1 after transfer of nanostructures to the device has been completed. [Figure 4a] FIG. 2 is a top view of a growth substrate according to an embodiment of the present invention. [Figure 4b] FIG. 4b is an enlarged detail of the rectangular area marked by dashed lines in FIG. 4a, in which multiple radially extending portions of the growth substrate are visible. [Figure 4c] FIG. 4b is an enlarged detail of the rectangular area marked by the dashed line in FIG. 4b, in which a single radially extending portion of the growth substrate is visible. [Figure 4d] An enlarged detail of the rectangular area marked by dashed lines in Figure 4c, where cantilever pairs in the radially extending portion of the growth substrate visibly contain nanostructures carried by some of the cantilever pairs. [Figure 5a] 4b is a perspective view of an apparatus according to an embodiment of the invention during attachment of nanostructures to a device substrate using the growth substrate of FIG. 4a. [Figure 5b]FIG. 5b is a side view of the device of FIG. 5a. [Figure 5c] FIG. 5b is a top view of the device of FIG. 5a. [Figure 5d] FIG. 5c is an enlarged detail of the rectangular area marked by the dashed line in FIG. [Figure 5e] FIG. 5d is an enlarged detail of the rectangular area marked by the dashed line in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0043] 1 to 3 show a support substrate in the form of a growth substrate 1 according to the prior art in various positions relative to a device substrate 3. As can be seen, the state-of-the-art growth substrate 1 has an overall flat rectangular shape and comprises a number of cantilever pairs 13 arranged parallel along one side of a main part 14 of the growth substrate 1. A nanostructure 2 is held in each case between at least a part of the cantilever pair 13 and can be, for example, in the form of a carbon nanotube. The nanostructure 2 preferably extends perpendicular to the extension of the cantilevers.

[0044] The device substrate 3 comprises a plurality of devices 31, typically arranged in several parallel rows next to each other, as can be seen, for example, in FIG. 5c. To transfer the nanostructures 2 to the devices 31, the growth substrate 1 is positioned near the device substrate 3 so that the cantilever pairs 13 holding the nanostructures 2 are positioned above the devices to which the respective nanostructures 2 will be attached (FIG. 1). The growth substrate 1 is then lowered relative to the device substrate 3 along the direction indicated by the arrow in FIG. 1 until the nanostructures 2 contact the devices 31 in the desired position and orientation (FIG. 2). The growth substrate 1 is then further lowered and moved away from the device substrate 3. In doing so, the nanostructures 2 remain in their positions on the devices 31, as can be seen in FIG. 3.

[0045] The devices 31 to which the nanostructures 2 are attached can, for example, in each case form a transistor or other electrical circuit. As shown in Figure 3, the nanostructures 2 can be in the form of carbon nanotubes, particularly in devices 31 that form transistors, arranged to connect a drain 32 to a source 33 of the device 31. The locations on the device substrate 3 to which the nanostructures 2 are attached are referred to as attachment points 34.

[0046] As can be seen from Figure 1, the length of the growth substrate 1 along the edge that comprises the cantilever pairs 13 is limited by the distance d between the devices 31. If the length of the growth substrate 1 is too long, the cantilever pairs 13 will collide with adjacent devices 31. Typically, the device substrate 3 is in the form of a wafer of a given size (see Figure 5c), which means that the distance d between the devices 31 can only be increased by including fewer devices 31 per wafer. Therefore, state-of-the-art growth substrates 1 have limited scalability for industrial production of large numbers of identical or similar devices.

[0047] 4a-4d show a support substrate in the form of a growth substrate 1 according to an embodiment of the present invention. The support substrate is also referred to as growth substrate 1, since it serves here not only to support nanostructures 2 but also to pre-grow nanostructures 2. In other embodiments, it is of course possible that nanostructures 2 are not grown on the support substrate, but instead the support substrate merely serves to support nanostructures 2 for transferring them to a device substrate. Thus, the growth substrate 1 shown in FIGS. 4a-4d may generally be a support substrate that is not used for growing nanostructures.

[0048] As can be seen in Figure 4a, the growth substrate 1 has a circular periphery 11, i.e., a generally flat, plate-shaped configuration with a curved periphery 11. The growth substrate 1 further comprises a plurality of radially extending portions 15, each connected to a main portion 14 of the growth substrate 1 and extending radially outward from the main portion 14. The main portions 14 form a circular or ring-shaped region. The radially extending portions 15 are positioned at specific distances from each other along the periphery 11 of the growth substrate 1.

[0049] As can be seen from Figure 4d, a plurality of cantilever pairs 13 are provided on each radially extending portion 15. The cantilever pairs 13 of each radially extending portion 15 extend parallel to one another and together form a group 12 of a plurality of cantilever pairs 13 arranged at regular distances from one another (see Figures 4b to 4d).

[0050] The radially extending portions 15 can be made in one piece from the same material as the main portion 14. However, in certain embodiments, it is also possible that the radially extending portions 15 with the cantilever pairs 13 are made separately from the main portion 14 and are simply attached to the main portion 14. In this case, the radially extending portions can be made from the same or a different material as the main portion 14. In such embodiments, the radially extending portions 15 can be formed by the leading edge of the growth substrate 1 in each case, as shown, for example, in FIGS. 1-3 . Thus, by attaching the radially extending portions 15 to the periphery 11 of the main portion 14, the main portion 14, together with the radially extending portions 15, form a growth substrate 1 according to an embodiment of the present invention.

[0051] The arrangement of the cantilever pairs 13 along the curved periphery 11 of the growth substrate 1 provides the advantage that the growth substrate 1 can have a much larger number of cantilever pairs 13 compared to the state-of-the-art growth substrate 1 of Figures 1 to 3. Due to the curved periphery of the growth substrate and the non-parallel extension of the groups 12 of cantilever pairs 13, there is no risk of collision with adjacent devices 31 during the transfer of the nanostructures 2 onto the devices 31.

[0052] Figures 5a-5e show a preferred embodiment of an apparatus 4 that serves to attach nanostructures 2 grown or deposited on a support substrate of the present invention to a device substrate 3. The support substrate can be in the form of a growth substrate 1 such as one of Figures 4a-4d.

[0053] The apparatus 4 comprises a holder 41 for holding the growth substrate 1, preferably in such a way that the growth substrate 1 can be released from the holder 41. The holder 41 is attached to a rotating disk 42 of the apparatus 4. The rotating disk 42, together with the holder 41 and the growth substrate 1 attached to the holder 41, is rotatable about a rotation axis R. The rotating disk 42 is further attached to a pivot block 43 of the apparatus 4, which allows the rotating disk 42, and thus the rotation axis R, to be tilted at an inclination angle α with respect to a geometric normal N of the device substrate 3. The geometric normal N is defined by a device substrate plane P, in which the attachment point 34 of the device substrate 3 is located. In this case, the device substrate plane P coincides with the flat upper surface of the device substrate 3. The pivot block 43 is pivotally attached to a connecting block 44, which is held by a mounting bracket 45.

[0054] The device substrate 3 is held by a positioner 46, which may be, but is not necessarily, stationary. The positioner 46 serves to hold and position the device substrate 3 relative to the growth substrate 1.

[0055] The ability to rotate the growth substrate 1 allows the nanostructures 2 held by pairs of cantilevers 13 to be transferred to the device substrate 3 one at a time.

[0056] The tilt of the rotation axis R with respect to the normal N allows for a particularly accurate transfer of the nanostructures 2 onto the device 31 with a significantly reduced risk of the growth substrate 1 or part of the device 4 colliding with the device substrate 3. In this respect, with reference to Figure 5b, it can be seen that due to the tilt of the rotation axis R with respect to the normal N of the device substrate 3, only a small part of the periphery 11 of the growth substrate 1 comes into contact with the device substrate 3.

[0057] 5a and 5b, the mounting bracket 45, and thus the apparatus 4, can be displaced along the x and y directions (x and y in FIG. 5a) to transfer the nanostructures 2 to a plurality of attachment points 34 at which the nanostructures 2 are attached to the device substrate 3. The x and y directions extend perpendicular to each other and in each case perpendicular to the geometric normal N of the device substrate plane P at which the attachment points 34 are located.

[0058] In certain embodiments, the apparatus 4 as shown in Figures 5a and 5b may also be adapted to be rotated as a whole about a rotation axis R. Such rotation of the entire apparatus 4 may be advantageous to correct for alignment errors prior to transfer of the nanostructures 2.

[0059] Figures 5d and 5e show detailed views of the growth substrate 1 and device substrate 3 during transfer of nanostructures 2 using apparatus 4. The ability to precisely position a particular cantilever pair 13 of the growth substrate 1 relative to the device substrate 3 is particularly apparent from Figures 5d and 5e. Due to the curved periphery of the growth substrate 1, only a single radial extension 15 associated with each group 12 of cantilever pairs 13 contacts the device substrate 3. The fork length l of each radial extension 15, measured perpendicular to the extension of the respective cantilever pair 13, is dimensioned to be shorter than the distance d between the devices 31. In this manner, there is no risk of the radial extension 15 colliding with an adjacent device 31 during transfer of the nanostructures 2. Nanostructures 2 held by the same group 12 of cantilever pairs 13 can be transferred to the device substrate 3 one after the other before the growth substrate 1 is rotated about the rotation axis R to transfer the nanostructures 2 of the other group 12 to the device substrate 3. Numerous nanostructures 2 in multiple groups 12 can be transferred in this manner without the need to change the growth substrate 1 .

[0060] The present invention is, of course, not limited to the embodiment shown in the figures. Many different modifications are possible. For example, the main portion 14 of the support or growth substrate does not necessarily have to have a circular perimeter. Instead, the main portion 14 can have a polygonal perimeter, such as a triangular, square, rectangular, or any other polygonal perimeter having five or more corners / edges. The cantilever pairs do not necessarily have to be arranged along the entire perimeter 11, but may be arranged along only a portion of the perimeter. Further modifications are possible. [Explanation of symbols]

[0061] 1. Growth substrate 11 Surroundings 12 groups 13 Cantilever Pair 14 Main parts 15 Radial extension 2 Nanostructures 3 Device substrate 31 devices 32 Drain 33 Source 34 Attachment point 4 equipment 41 Holder 42 Rotating disc 43 Pivot Block 44 Connection Blocks 45 Mounting bracket 46 Positioner R rotation axis X x direction Y y direction α Incline angle d Device distance l Fork length N normal P device substrate plane

Claims

1. A support substrate (1) for a plurality of nanostructures (2), in particular carbon nanotubes, comprising: The support substrate (1) comprises a plurality of cantilever pairs (13) each configured to hold a nanostructure (2) therebetween; A support substrate (1), wherein at least some of the plurality of cantilever pairs (13) are arranged to extend in different non-parallel directions along at least a curved or angled portion of the periphery (11) of the support substrate (1).

2. 2. The support substrate (1) of claim 1, wherein the plurality of cantilever pairs (13) are distributed along the entire periphery (11) of the support substrate (1).

3. 3. The support substrate (1) according to claim 1 or 2, wherein each of the pair of cantilever beams (13) extends outwardly along a substantially radial direction.

4. 4. A support substrate (1) according to any one of claims 1 to 3, wherein the periphery (11) of the support substrate (1) describes, as a whole, a circle or a regular polygon.

5. 5. The support substrate (1) according to any one of claims 1 to 4, wherein the cantilever pairs (13) are arranged in groups (12) of a plurality of cantilever pairs (13) extending parallel to one another.

6. 6. The support substrate (1) of claim 5, wherein the groups (12) of the plurality of cantilever pairs (13) extending parallel to one another are arranged at regular distances, preferably along the entire periphery (11) of the support substrate (1).

7. 7. The support substrate (1) according to claim 5 or 6, wherein any two adjacent groups (12) of cantilever pairs (13) extending parallel to each other form an angle of 10° or less, preferably 8° or less, more preferably 6° or less with respect to each other.

8. The support substrate (1) according to any one of claims 1 to 7, wherein the plurality of cantilever pairs (13) extend in a common plane.

9. An apparatus (4) for depositing a plurality of nanostructures (2), in particular carbon nanotubes, onto a device substrate (3), comprising: A holder (41) for holding a support substrate (1) according to any one of claims 1 to 8, comprising a plurality of cantilevers (13) extending in different non-parallel directions in a common plane; a positioner (46) for positioning the device substrate (3) onto which one or more of the plurality of nanostructures (2) are attached relative to the support substrate (1); the apparatus (4) is configured to move the holder (41) and the positioner (46) relative to each other so that the nanostructures (2), each held between a pair of cantilevers (13), are transferred from the support substrate (1) to a plurality of attachment points (34) on the device substrate (3) for attachment to the device substrate (3); The apparatus (4) is configured to rotate the support substrate (1) around a rotation axis (R) extending vertically through the common plane of the multiple cantilever pairs (13) to continuously attach the nanostructures (2) to the device substrate (3).

10. 10. The apparatus (4) according to claim 9, wherein the rotation axis (R) is tilted or tiltable with respect to a geometric normal (N) of a device substrate plane (P) in which the attachment point (34) is located.

11. 11. The apparatus (4) according to claim 10, wherein the rotation axis (R) is inclined or can be inclined with respect to the geometric normal (N) of the device substrate plane (P) at an inclination angle (α) in the range of from 1° to 40°, preferably from 4° to 20°, particularly preferably from 4° to 10°.

12. The apparatus (4) according to any one of claims 9 to 11, wherein the apparatus (4) is configured to move the support substrate (1) relative to the positioner (46) along an x-direction (x) extending perpendicular to a geometric normal (N) of a device substrate plane (P) in which the attachment point (34) is located.

13. The apparatus (4) of claim 12, further configured to move the support substrate (1) relative to the positioner (46) along a y-direction (y) extending perpendicular to both the x-direction (x) and the geometric normal (N).

14. A method for depositing a plurality of nanostructures (2), in particular carbon nanotubes, on a device substrate (3), in particular using an apparatus (4) according to any one of claims 9 to 13, comprising the steps of: Each of the nanostructures (2) is arranged between a pair of cantilevers (13) of a support substrate (1) according to any one of claims 1 to 8, the pair of cantilevers (13) extending in different non-parallel directions in a common plane; The method includes at least a step of rotating the support substrate (1) about a rotation axis (R) extending vertically through the common plane to continuously transfer the nanostructures (2) from the support substrate (1) to a plurality of attachment points (34) on the device substrate (3) in order to attach the nanostructures (2) to the device substrate (3).

15. 15. The method of claim 14, wherein, to attach the nanostructure (2) to the device substrate (3), the rotation axis (R) is tilted with respect to a geometric normal (N) of a device substrate plane (P) in which the attachment point (34) is located.

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