Method and system for depositing a nano-object on a receiving surface and fastening system incorporating such a deposition system

Abstract

The invention relates to a method for depositing a nano-object (4) on a receiving surface (20) comprising a first step of picking up this nano-object (4) located on a carrying surface, a step of transferring the picked-up nano-object (4) to the receiving surface (20), and a step of depositing the nano-object (4) on the receiving surface (20), which method is characterised in that it use a cantilever transfer device (4) comprising two spaced-apart arms (31, 32) arranged to pick up, hold and release the nano-object.

Description

Method and system for depositing a nano-object on a receiving surface, and stapling system integrating such a deposition system FIELD OF THE INVENTION

[0001] The present invention relates to a method and a system for depositing a nano-object on a receiving surface. It also relates to a stapling system integrating such a deposition system. The field of the invention is more particularly that of quantum components and systems. STATE OF THE ART

[0002] Depositing nanotubes on a surface is currently a real technological challenge, due to their extremely small dimensions. It is even more difficult when it comes to depositing a nanotube on two electrodes spaced apart by a trench.

[0003] The paper “One-step Direct Transfer of Pristine Single-Walled Carbon Nanotubes for Functional Nanoelectronics”, Chung Chiang Wuet al., Nanoletters 2010,[1], discloses a one-step direct transfer technique for the fabrication of functional nanoelectronic devices using pristine single-walled carbon nanotubes (SWNTs). The suspended SWNTs grown by the chemical vapor deposition (CVD) method are aligned and directly transferred onto pre-patterned device electrodes at room temperature.

[0004] The paper “Fork stamping of pristine carbon nanotubes onto ferromagnetic contacts for spin-valve devices”, J. Gramichet al., Phys. Status, 2015[2], discloses a fabrication process called “fork stamping” optimized for the dry transfer of individual pristine carbon nanotubes (CNTs) onto ferromagnetic contact electrodes fabricated by standard lithography.

[0005] The paper "Transfer of carbon nanotubes onto microactuators for hysteresis-free transistors at low thermal budget"M. Muothand C. Hierold, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS), 2012, pp. 1352-1355, doi:10.1109 / MEMSYS.2012.6170417,[3], discloses a dry transfer process for single-walled carbon nanotubes, enabling the production of ultraclean, hysteresis-free suspended nanotube field-effect transistors on microactuated electrodes without exposing the device chip to high nanotube growth temperatures. The nanotubes are grown on a separate die between the arms of a fork structure and are then transferred to receiving electrodes of a device die. The device die is kept at room temperature; and thus it can in principle contain temperature-sensitive readout circuits.Liquid-free transfer at room temperature is performed under optical microscope observation, while placement is detected by monitoring the current through the device electrodes.

[0006] The document WO2020079228A1 (Delbecq et al.) discloses a method and device for depositing a nano-object, comprising an approach, in an enclosure, of a support towards a carrier substrate, then - a transfer, in the enclosure, of the object from the support to a deposition zone of the carrier substrate. The transfer step is preferably carried out while the interior of the enclosure is under vacuum at a pressure of less than 10 -6 bar.

[0007] As an example of prior art, a stapling chamber 2 maintained under ultra-high vacuum (UHV) is an integral part of nanofabrication equipment 1 as shown in. The stapling chamber comprises a chip 20 provided with electrodes 23, on which it will be necessary to deposit a carbon nanotube initially present on cantilevered electrodes 23 extending an electronic circuit or chip 21, with reference to FIGS. 2 to 5.

[0008] Current methods for assembling Qubit components use a nanotube stapling technique in which it is difficult to control the approach angle of the chip 21 provided with electrodes 23 carrying nanotubes relative to the plane of the receiving chip, as illustrated in. It is also almost impossible to precisely position the nanotubes and to determine a stop in the transfer of a nanotube along the vertical axis.

[0009] Furthermore, the receiving surface is usually provided with large trenches, which could be a source of degradation of the resonator quality factor. Furthermore, the stapling technique is not scalable beyond a few Qubits. Moreover, navigation inside a stapler is particularly difficult.

[0010] One initial solution was to eliminate the trench entirely by using a chip with electrodes on an arm instead of electrodes over a trench. But the problem with this design is that it would change the entire nanofabrication process. The goal, therefore, is to solve the problem without changing the chip design.

[0011] Hierold et al., 2012 had the idea of ​​building the chip on a cantilever or cantilever, the transfer of the carbon nanotube is only a transfer between two cantilevers. This was not possible, as it would require a substantial change in the chip design.

[0012] An aim of the present invention is to propose a new technique for transferring a nano-object onto an electronic chip / circuit in a coherent manner, with the fewest possible defects on the resulting chip, as quickly as possible and as scalably as possible.

[0013] According to a first aspect, the objective of the present invention is thus achieved with a method for depositing at least one nano-object on a receiving surface, this nano-object being initially arranged on a cantilever chip having a comb structure, characterized in that it comprises: a step for gripping this nano-object, this gripping step implementing a cantilever device or transfer fork comprising two spaced arms each provided with a tooth, the two teeth being opposite each other and arranged to grip, hold and release said nano-object, a step for transferring said nano-object thus gripped to the receiving surface, and a step for depositing said nano-object on the receiving surface.

[0014] According to a second aspect, the objective of the present invention is thus achieved with a method for depositing a nano-object on a receiving surface, comprising a first step for gripping this nano-object placed on a carrying surface, a step for transferring said nano-object thus gripped to the receiving surface, and a step for depositing said nano-object on the receiving surface, characterized in that it implements a cantilever transfer device or a transfer fork comprising two spaced arms arranged to grip, hold and release said nano-object.

[0015] Other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination, may be combined with the first aspect or the second aspect.

[0016] In particular, a deposition method is provided for depositing a nano-object, or at least one nano-object, in particular at least one carbon nanotube, on a receiving surface, comprising a first step for gripping this nano-object, or at least this nano-object, or this at least one carbon nanotube, arranged on a carrying surface, in particular a cantilever chip or a cantilever semiconductor chip.

[0017] According to one embodiment, the at least one nano-object is initially arranged on cantilever electrodes, in particular cantilever electrodes of a cantilever chip or a cantilever semiconductor chip.

[0018] Preferably, the cantilever transfer device or the transfer fork comprises two spaced arms each provided with a tooth, the two teeth being opposite each other and arranged to grasp, hold and release said nano-object, or carbon nanotube.

[0019] When the method according to the invention is implemented for the deposition of at least one nano-object or at least one carbon nanotube, the carrying surface may comprise a cantilevered semiconductor chip.

[0020] When the method according to the invention is implemented for stapling at least one nano-object or at least one carbon nanotube, the carrying surface may comprise a cantilevered semiconductor chip.

[0021] The deposition method according to the invention can be advantageously implemented for the deposition of at least one nanotube, preferably at least one carbon nanotube on electrodes separating trenches.

[0022] Preferably, during the step of depositing at least one nano-object, or one or more nanotubes, the arms of the cantilever transfer device penetrate into two trenches surrounding an electrode.

[0023] These electrodes can be advantageously arranged to produce Qubit components.

[0024] With the deposition method according to the invention, it is possible to produce deposits of nano-objects or nanotubes on circuits having inter-electrode trenches of width less than 100 μm, typically 30 μm.

[0025] Preferably, a step is provided for detecting contact of the transfer cantilever device with the receiving surface, this detection step implementing an atomic force probe comprising a tip carrying the transfer cantilever device and fixed to a tuning fork or mechanical resonator controlled in frequency around a predetermined resonance frequency.

[0026] Preferably, the detection step comprises a step for delivering information on the distance between the tip carrying the transfer cantilever device and the receiving surface, said distance information being processed to control the transfer step.

[0027] According to one example, the method is implemented for the deposit of at least one nanotube, in particular at least one carbon nanotube on a microelectronic circuit.

[0028] Preferably, the step of transferring the at least one nanotube, in particular at least one carbon nanotube, is arranged to deposit it on electrodes.

[0029] According to any embodiment, the method can be implemented in the realization of a Qubit component.

[0030] According to another aspect of the invention, a system is proposed for depositing at least one nano-object on a receiving surface, implementing the deposition method according to the invention, comprising means for gripping this nano-object arranged on a carrying surface, preferably a cantilever chip, means for transferring said nano-object thus gripped to the receiving surface, and means for depositing said nano-object on the receiving surface. It comprises, as said gripping, transfer and depositing means, at least one cantilever transfer device or at least one transfer fork comprising two spaced arms arranged to grip, hold and release said nano-object.

[0031] In particular, a deposition system is proposed for depositing a nano-object on a receiving surface, implementing the deposition method according to the invention, comprising means for gripping this nano-object placed on a carrying surface.

[0032] Preferably, the at least one cantilever transfer device or the at least one transfer fork comprises two spaced arms each provided with a tooth, these teeth being opposite each other and arranged to grasp, hold and release said nano-object.

[0033] Preferably, the cantilever transfer device can be produced in the form of two substantially parallel blades spaced apart by an insulating piece.

[0034] Each blade may for example comprise an elongated portion of which one cantilevered end comprises an arm substantially perpendicular to said elongated portion.

[0035] These arms may have an electrically conductive coating.

[0036] The deposition system according to the invention can be advantageously implemented for the deposition of at least one carbon nanotube on electrodes separated by trenches.

[0037] Preferably, the inter-electrode trenches are less than 100 μm wide.

[0038] Preferably, said system is implemented in a system for stapling nanotubes, in particular carbon nanotubes, on a plurality of electrodes of an electronic circuit of a quantum dot.

[0039] In a particular implementation of the invention, a system is provided for stapling nanotubes, in particular carbon nanotubes, on a plurality of electrodes, comprising a deposition system according to the invention, a stapling device and a device for receiving an electronic circuit of a quantum dot.

[0040] Preferably, the system further comprises means for detecting contact or risk of contact of the transfer cantilever device with the receiving surface, these detection means comprising an atomic force probe comprising a tip carrying the transfer cantilever device and fixed to a tuning fork controlled in frequency around a predetermined resonance frequency.

[0041] Preferably, the detection means further comprise means for delivering information on the difference between the tip carrying the cantilever transfer device and the receiving surface, and in that it further comprises means for controlling the transfer means from said information on the difference.

[0042] According to one embodiment, said system is arranged in a stapling chamber within a system for producing Qubit components.

[0043] According to one variant, a system is provided for stapling carbon nanotubes in order to produce Qubit components, comprising a stapling chamber integrating a deposition system according to one of the preceding characteristics.

[0044] With the present invention, the carbon nanotube is transferred onto a small, single cantilevered intermediate. This allows the trench to be much smaller, saving space on the chip for future scalable design. REFERENCES

[0045] [1] “One-step Direct Transfer of Pristine Signe-Walled Carbon Nanotubes for Functional Nanoelectronics”, Chung Chiang Wu et al., Nanoletters 2010

[0046] [2] “Fork stamping of pristine carbon nanotubes onto ferromagnetic contacts for spin-valve devices”,J. Gramichet al., Phys. Status, 2015

[0047] [3] “Transfer of carbon nanotubes onto microactuators for hysteresis-free transistors at low thermal budget”M. Muothand C. Hierold, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS), 2012, pp. 1352-1355, doi:10.1109 / MEMSYS.2012.6170417

[0048] [4]MicroMegascope (Canale et al.), arXiv:1805.05231v1 [physics.ins-det] May 14, 2018 DESCRIPTION OF FIGURES

[0049] is a perspective view of a prior art stapling chamber;

[0050] is a view of the interior of the stapling chamber of the ;

[0051] represents a receiving substrate and a multi-electrode circuit implemented in a prior art deposition method;

[0052] illustrates an example of a cantilever array chip approaching two trenches separated by a set of aligned electrodes, of the prior art;

[0053] represents an example of a multi-electrode circuit implemented in a prior art deposition method;

[0054] illustrates an example, in the prior art, of an approach made difficult by imperfect angle control of the multi-electrode circuit on a receiving substrate in the prior art;

[0055] represents an exemplary embodiment of a cantilever transfer device implemented in a nanotube deposition system according to the invention;

[0056] is an enlarged view of one end of the cantilever transfer device;

[0057] represents a nanotube present on a multi-electrode circuit;

[0058] represents a top view and a side view of an approach to a cantilever transfer device, for a first transfer of the nanotube of the;

[0059] illustrates a situation of transfer of the nanotube by a cantilever transfer device;

[0060] represents an approach to a cantilever transfer device, for a second transfer of the nanotube;

[0061] represents the cantilever device for transferring the nanotube carrier, which has come into contact with the electrodes, for a second transfer;

[0062] illustrates the nanotube on the substrate, after a second transfer;

[0063] illustrates the drastic reduction in the size of a trench, made possible by the deposition process according to the invention;

[0064] illustrates the space saving obtained by reducing the size of the trenches;

[0065] illustrates an example of implementation of the deposition method according to the invention;

[0066] is a perspective view of an exemplary embodiment of a stapling system according to the invention;

[0067] is a cutaway view of the stapling system shown in;

[0068] is an enlarged view of the interior of the stapling system shown in Figures 18 and 19;

[0069] includes a top view of the AFM device equipping the stapling system shown in Figures 18, 19 and 20, and an enlarged view of an electronic circuit treated with the deposition method according to the invention;

[0070] is an enlarged perspective view of the AFM device shown in ;

[0071] is an enlarged view of the cantilever transfer device coupled to the AFM device of the ; and

[0072] This is a detailed view of the AFM device of the. DETAILED DESCRIPTION

[0073] We will first describe, with reference to Figures 7 and 8, an exemplary embodiment of a cantilever transfer device 3. This transfer device 3 comprises two elongated blades 310, 320 spaced apart by a piece of insulating material. These two blades 310, 320 have at one of their ends a bent arm 31, 32 and at the other of their ends a part allowing attachment to a mechanical stapling device (not shown) arranged in a stapling chamber.

[0074] The cantilever transfer device 3 is designed to take a carbon nanotube 4 arranged on cantilevers 41; 42 of a support structure 23, with reference to FIGS. 9 and 10.

[0075] When the arms 31; 32 of the cantilever transfer device 3 come into contact with the nanotube 4, it is held fixed by the action of Van Der Waals forces. The transfer device 3 can then take the nanotube towards a receiving structure, with reference to figures 11 to 12. The cantilever transfer device 3 carrying the nanotube 4 approaches a receiving structure accommodating an electronic chip 5 arranged between two trenches and then deposits this nanotube 4 on the chip 5, as illustrated in figures 13, 14 and 17.

[0076] It should be noted that the transfer and deposition technique provided by the invention makes it possible to significantly reduce the width of the trenches of the receiving structures, as illustrated in FIGS. 15 and 16. It is thus possible to go from a trench width of approximately 3 mm to a trench width of approximately 30 μm. Thus, the receiving chip 5 is arranged on a protruding part 26 between two trenches of very small thickness. The nanotube 4 can then be deposited on the receiving chip 5 arranged between two trenches 41, 42 and connected to a circuit 6 arranged on the receiving structure 20, as illustrated in FIG.

[0077] In the nanotube deposition method according to the invention, an intermediate fork, realized by the transfer cantilever device, is used to perform two transfers of a target carbon nanotube. First, the fork is essentially used to "pluck" a nanotube suspended between two cantilevers on a cantilever growth chip having a comb structure. After this transfer, the nanotube is fixed to the tip of the fork, suspended between its two prongs. The fork with the attached nanotube is then brought into contact with the chip of a qubit device to precisely transfer this nanotube onto the source and drain electrodes, suspended above an array of gate electrodes. A more detailed overview of the intermediate fork design and transfer processes is presented below.

[0078] The intermediate fork—or transfer cantilever—consists of two microfabricated prongs attached to a rectangular support base. The fork and its base can be fabricated from an insulating material such as silicon or silicon nitride (the specific material is irrelevant) using conventional lithography and etching techniques. The tips of the prongs must be metallized and electrically connected to the supports' base's flares, either by blanket evaporation or lithography. This connectivity is essential for the second transfer process to the qubit chip and can also facilitate the first transfer from the growth chip.

[0079] The fork width is limited by the requirement to fit between the cantilever pairs on the growth chip for the first transfer (approximately 30 μm). The gap between the fork prongs must be large enough for the outermost qubit device electrodes to fit between the prongs for the second transfer (approximately 10 μm). The prongs must also be long enough so that the fork tip can be easily resolved with an optical microscope when oriented at a small angle (approximately 2 degrees) from the normal, as shown in . It is further required that the prongs be substantially longer than the thickness of the growth cantilevers as well as the depth of the trenches / pits on the qubit chip to facilitate ease of nanotube transfer. Therefore, prongs in the range of 100–500 μm in length are required.Finally, the teeth must be thick enough to provide a large enough surface area for the nanotube to be attached to their tip during the first transfer, and must therefore have a thickness of approximately 10 µm. This thickness also impacts the mechanical robustness of the teeth, which are intended to survive many nano-assembly cycles.

[0080] The first transfer begins by optically aligning the fork tip over the location of the target nanotube suspended between two cantilevers on the growth chip. Once aligned, the fork is then lowered to bring the metallized fork tips into contact with the suspended nanotube.

[0081] We will now describe, with reference to figures 18 to 24, a particular embodiment of a stapling system according to the invention, providing detection of the contact of the cantilever transfer device with the receiving surface and implementing an atomic force microscope architecture.

[0082] Document WO2021009290A1 (Niguès et al.) discloses an atomic force microscope for evaluating a surface of a sample, comprising a sample holder, having a first zone adapted to receive the fixedly mounted sample, a probe having a tip suitable for being positioned opposite the surface of the sample, the microscope being configured to allow adjustment of a position of the tip relative to the surface and a support, the sample holder having at least a second zone, distinct from the first zone and fixed relative to the support, the sample holder being deformable so as to allow relative movement of the first zone relative to the second zone, and the microscope comprising a detector suitable for detecting movement of the first zone relative to the second zone.

[0083] The MicroMegascope (Canale et al.), 2018 [4], discloses an atomic force imaging device with a centimeter-scale oscillator. With this device, it becomes possible to produce topographic images with a resolution of the order of a nanometer, with a centimeter-sized tuning fork or mechanical resonator equipped with an accelerometer to measure the oscillation of the resonator.

[0084] An AFM (Atomic Force Microscope) technique can be used to detect when the tip of the cantilever is close to the trench. The problem was that this required a substantial change in the cantilever design. This is because in the AFM technique, the oscillator is very small and difficult to integrate into any design.

[0085] The stapling system includes, with reference to Figures 23 and 24, a fork transfer probe 10 coupled to a tuning fork (or mechanical resonator) and nanopositioner assembly 200. To take advantage of AFM detection during the transfer process, the fork probe 10, implemented as a microchip attached to the printed circuit 100, is attached to the end 121 of a tuning fork or mechanical resonator - inspired by the micromegascope described in the aforementioned document [4] - which is mounted on a stack 130 of x / y / z nanopositioning motors.

[0086] The vibration of the tuning fork 200 is driven by a piezoelectric actuator 120 mounted on top of the tuning fork 200. A MEMS (Micro Electro Mechanical Systems) accelerometer chip 122, attached to the side of the tuning fork 200 near the tip, is used to detect the movement of the tuning fork 200. The fork probe 10, as attached to the tip of the tuning fork 200, will transduce the interactions between its tip and the surfaces / nanotubes during the transfer process, disturbing the vibration of the tuning fork 200.

[0087] These changes in vibration of the tuning fork 200 are then measured by the accelerometer and electrically encoded. A phase-locked loop (PLL) controller (external electronics, not shown) is used to retract and extend the nanopositioning motor on the z-axis based on the signal from the accelerometer 122. The PLL can then be configured to trigger an alarm when the tip of the fork transfer probe 10 contacts a nanotube or surface 20, and to prevent collisions by maintaining a safe separation between the tip of the probe 10 and the surface of the quantum circuit chip.

[0088] Of course, the present invention is not limited to the examples which have just been described and numerous other configurations can be envisaged without departing from the scope of the invention.

Claims

A method for depositing at least one nano-object (4) onto a receiving surface (20), this nano-object being initially arranged on a cantilever chip having a comb structure, characterized in that it comprises: a step for grasping this nano-object (4), this grasping step implementing a cantilever device or transfer fork (3) comprising two spaced arms (31, 32) each provided with a tooth, the two teeth being opposite each other and arranged to grasp, hold and release said nano-object (4), a step for transferring said nano-object (4) thus grasped to the receiving surface (20), and a step for depositing said nano-object (4) onto the receiving surface (20). Deposition method according to the preceding claim, implemented for the deposition of at least one nano-object (4) on electrodes separating trenches. Deposition method according to the preceding claim, characterized in that during the deposition step of at least one nano-object, the arms of the cantilever transfer device penetrate into two trenches surrounding an electrode. Deposition method according to the preceding claim, characterized in that the inter-electrode trenches are less than 100 μm wide. Deposition method according to any one of the preceding claims, characterized in that it further comprises a step for detecting contact of the transfer cantilever device (30) with the receiving surface (20), this detection step employing an atomic force probe (1) having a tip (10) carrying the transfer cantilever device (30) and fixed to a tuning fork or mechanical resonator (11,12) frequency controlled around a predetermined resonance frequency. Deposition method according to the preceding claim, characterized in that the detection step includes a step to deliver a gap information between the tip (10) carrying the cantilever transfer device (30) and the receiving surface (20), said distance information being processed to control the transfer step. Deposition method according to the preceding claim, implemented for the deposition of at least one carbon nanotube (4) on a microelectronic circuit (20). Deposition method according to the preceding claim, characterized in that the transfer step of at least one carbon nanotube (4) is arranged to deposit it on electrodes. Deposition method according to any one of the preceding claims, characterized in that it is implemented in the realization of a Qubit component. System (10) for depositing at least one nano-object (4) onto a receiving surface (20), implementing the deposition method according to any one of the preceding claims, comprising means (3) for grasping this nano-object disposed on a carrying surface (21), means for transferring said nano-object thus grasped to the receiving surface (20), and means for depositing said nano-object (4) onto the receiving surface (20), and comprising, as means of said grasping, transferring and depositing, at least one cantilever transfer device (3) comprising two spaced arms (31, 32) each provided with a tooth, these teeth being opposite each other and arranged to grasp, hold and release said nano-object (4), characterized in that the cantilever transfer device (3) is made in the form of two substantially parallel blades (310, 320) separated by an insulating piece (33). Deposition system (10) according to the preceding claim, characterized in that each blade (310, 320) comprises an elongated part having an overhanging end with an arm substantially perpendicular to said elongated part. Deposition system according to the preceding claim, characterized in that the arms comprise an electrically conductive coating. Deposition system according to any one of claims 10 to 12, implemented for the deposition of at least one carbon nanotube on electrodes separated by trenches. Deposition system according to the preceding claim, characterized in that the inter-electrode trenches are less than 100 μm wide. Deposition system according to any one of claims 10 to 14, characterized in that it is implemented in a system for stapling nanotubes onto a plurality of electrodes of an electronic circuit of a quantum dot. Deposition system according to any one of claims 10 to 15, characterized in that it further comprises means (1) for detecting contact or risk of contact of the transfer cantilever device (3, 30) with the receiving surface (20), these detection means comprising an atomic force probe (1) having a tip (10) carrying the transfer cantilever device (3, 30) and fixed to a tuning fork (11, 12) frequency controlled around a predetermined resonance frequency. Deposition system (2) according to the preceding claim, characterized in that the detection means further include means for delivering a gap information between the tip (10) carrying the cantilever transfer device (3, 30) and the receiving surface (20), and in that it further includes means for controlling the transfer means from said gap information. Deposition system according to the preceding claim, characterized in that it is arranged in a stapling chamber within a system for making Qubit components. System for stapling carbon nanotubes to produce Qubit components, comprising a stapling chamber incorporating a deposition system according to one of the three preceding claims.

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