Method and system for depositing a nano-object onto a receiving surface, and stapling system incorporating such a deposition system

Abstract

A method for depositing a nano-object (4) onto a receiving surface (20), comprising a first step for grasping the nano-object (4) disposed on a carrying surface, a step for transferring the grasped nano-object (4) to the receiving surface (20), and a step for depositing the nano-object (4) onto the receiving surface (20), characterized in that it employs a cantilever transfer device (3) comprising two spaced arms (31, 32) arranged to grasp, hold, and release the nano-object (4). See Figure 17

Description

Title of the invention: Method and system for depositing a nano-object onto a receiving surface, and stapling system incorporating such a deposition system. FIELD OF THE INVENTION

[0001] The present invention relates to a method and a system for depositing a nano-object onto a receiving surface. It also relates to a stapling system incorporating 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 onto a surface is currently a real technological challenge, due to the very small dimensions of these nanotubes. It is even more difficult when it comes to depositing a nanotube onto two electrodes separated by a trench.

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

[0004] The document “Fork stamping of pristine carbon nanotubes onto ferromagnetic contacts for spin-valve devices”, J. Gramich et al., Phys. Status, 2015 [2], discloses a manufacturing 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" by M. Muoth and 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 method for single-walled carbon nanotubes, enabling the production of ultraclean, hysteresis-free suspended nanotube field-effect transistors on micro-actuated electrodes without exposing the device chip to high nanotube growth temperatures. The nanotubes are grown on a separate matrix, between the arms of a fork structure, and are then transferred onto receiving electrodes of a device matrix. The device matrix is maintained 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's electrodes.

[0006] Document WO2020079228A1 (Delbecq et al.) discloses a method and device for depositing a nano-object, comprising approaching a support within an enclosure towards a carrier substrate, and then transferring the object from the support to a deposition zone within the enclosure. The transfer step is preferably carried out while the inside of the enclosure is under vacuum at a pressure below 10⁶ bar.

[0007] By way of prior art example, a stapling chamber 2 maintained under ultra-high vacuum (UHV) is an integral part of a nanofabrication device 1 as shown in [Fig. 1]. The stapling chamber comprises a chip 20 equipped with electrodes 23, onto which a carbon nanotube initially present on cantilevered electrodes 23 extending an electronic circuit 21, as shown in Figures 2 to 5, will be deposited.

[0008] Current Qubit component assembly methods employ a nanotube stapling technique in which it proves difficult to control the approach angle of a chip 21 equipped with electrodes 23 carrying nanotubes relative to the plane of the receiving chip, as illustrated in [Fig. 6]. Furthermore, it is virtually impossible to precisely position the nanotubes and to determine a point at which the transfer of a nanotube stops along the vertical axis.

[0009] Furthermore, the receiving surface is generally equipped with large trenches, which could constitute a source of degradation of the resonator's quality factor. Moreover, the stapling technique is not scalable beyond a few qubits. In addition, navigation within a stapling machine is particularly difficult.

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

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

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

[0013] 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 grasping this nano-object disposed on a carrying surface, a step for transferring said nano-object thus grasped 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 grasp, hold and release said nano-object.

[0014] In particular, a deposition method is provided for depositing a nano-object onto a receiving surface, comprising a first step for grasping this nano-object disposed on a carrying surface.

[0015] Preferably, the cantilever transfer device or 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.

[0016] When the process according to the invention is implemented for the deposition of a carbon nanotube, the carrying surface may include a cantilever semiconductor chip.

[0017] When the method according to the invention is implemented for stapling a carbon nanotube, the carrying surface may include a cantilever semiconductor chip.

[0018] The deposition process according to the invention can advantageously be implemented for the deposition of nanotubes on electrodes separating trenches.

[0019] Preferably, during the step of depositing a nanotube or several nanotubes, the arms of the cantilever transfer device penetrate into two trenches surrounding an electrode.

[0020] These electrodes can be advantageously arranged to make Qubit components.

[0021] With the deposition process according to the invention, it is possible to carry out nanotube deposits on circuits having inter-electrode trenches of width less than 100 sqm, typically 30 sqm.

[0022] Preferably, a step is proposed for detecting contact of the transfer cantilever device with the receiving surface, this detection step implementing an atomic force probe having a tip carrying the transfer cantilever device and fixed to a tuning fork or mechanical resonator frequency controlled around a predetermined resonance frequency.

[0023] Preferably, the detection step includes a step for delivering gap information between the tip (10) carrying the transfer cantilever device (30) and the receiving surface (20), said distance information being processed to control the transfer stage.

[0024] According to one example, the process is implemented for the deposition of a carbon nanotube on a microelectronic circuit.

[0025] Preferably, the step of transferring a nanotube is arranged to deposit it on electrodes.

[0026] According to any embodiment, the method can be implemented in the realization of a Qubit component.

[0027] According to another aspect of the invention, a system is proposed for depositing a nano-object onto a receiving surface, implementing the deposition process according to the invention, comprising means for grasping this nano-object disposed on a carrying surface, means for transferring said nano-object thus grasped to the receiving surface, and means for depositing said nano-object on the receiving surface, characterized in that it comprises, as means of said grasping, transferring and depositing, at least one cantilever transfer device or at least one transfer fork comprising two spaced arms arranged to grasp, hold and release said nano-object.

[0028] In particular, a deposition system is proposed for depositing a nano-object on a receiving surface, implementing the deposition process according to the invention, comprising means for grasping this nano-object disposed on a carrying surface.

[0029] 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.

[0030] The cantilever transfer device can be made in the form of two substantially parallel blades separated by an insulating piece.

[0031] Each blade may for example include an elongated part, one cantilevered end of which has an arm substantially perpendicular to said elongated part.

[0032] These arms may include an electrically conductive coating.

[0033] The deposition system according to the invention can advantageously be implemented for the deposition of nanotubes on electrodes separated by trenches.

[0034] Preferably, the inter-electrode trenches are less than 100 sqm wide.

[0035] Preferably, said system is implemented in a system for stapling nanotubes on a plurality of electrodes of an electronic circuit of a quantum dot.

[0036] In a particular embodiment of the invention, a system is proposed for stapling nanotubes onto a plurality of electrodes, comprising a deposition system according to the invention, a stapling device and a device for receiving an electronic circuit from a quantum dot.

[0037] Preferably, the system further comprises means for detecting contact or a risk of contact of the cantilever transfer device with the receiving surface, these detection means comprising an atomic force probe having a tip carrying the cantilever transfer device and fixed to a frequency-controlled tuning fork around a predetermined resonance frequency.

[0038] Preferably, the detection means further include means for delivering gap information between the tip carrying the cantilever transfer device and the receiving surface, and further include means for controlling the transfer means from said gap information.

[0039] According to one embodiment, said system is arranged in a stapling chamber within a system for realizing Qubit components.

[0040] 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.

[0041] With the present invention, the carbon nanotube is thus transferred onto a small, unique cantilever intermediate. This allows the trench to be much smaller, saving space on the chip for future scalable design. REFERENCES

[0042] [1] “One-step Direct Transfer of Pristine Signe-Walled Carbon Nanotubes for Functional Nanoelectronics”, Chung Chiang Wu et al., Nanoletters 2010

[0043] [2] “Fork stamping of pristine carbon nanotubes onto ferromagnetic contacts for spin-valve devices”, J. Gramich et al., Phys. Status, 2015

[0044] [3] "Transfer of carbon nanotubes onto microactuators for hysteresis-free transistors at low thermal budget" M. Muoth and C. Hierold, 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS), 2012, pp. 1352-1355, doi: 10.1109 / MEMSYS.2012.6170417

[0045] [4] ^MicroMegascope (Canale et al.), arXiv:1805.05231vl [physics.ins-det] 14 May 2018 DESCRIPTION OF THE FIGURES

[0046] [Fig.1] [Fig.1] is a perspective view of a prior art stapling chamber;

[0047] [Fig.2] [Fig.2] is a view of the inside of the stapling chamber of [Fig.1];

[0048] [Fig. 3] [Fig. 3] represents a receiving substrate and a multi-electrode circuit implemented in a prior art filing process;

[0049] [Fig.4] [Fig.4] illustrates an example of a cantilever network chip approaching two trenches separated by a set of aligned electrodes, of the prior art;

[0050] [Fig. 5] [Fig. 5] represents an example of a multi-electrode circuit implemented in a prior art deposit process;

[0051] [Fig.6] [Fig.6] illustrates an example, in the prior art, of an approach made difficult by an imperfect angle control of the multi-electrode circuit of [Fig.5] on a receiving substrate in the prior art;

[0052] [Fig.7] [Fig.7] represents an example of the realization of a cantilever transfer device implemented in a nanotube deposition system according to the invention;

[0053] [Fig.8] [Fig.8] is an enlarged view of one end of the cantilever transfer device of [Fig.7];

[0054] [Fig.9] [Fig.9] represents a nanotube present on a multi-electrode circuit;

[0055] [Fig. 10] [Fig. 10] represents a top view and a side view of an approach of a cantilever transfer device, for the purpose of a first transfer of the nanotube from [Fig.9];

[0056] [Fig. 11] [Fig. 11] illustrates a situation of transfer of the nanotube by a cantilever transfer device;

[0057] [Fig. 12] the [Fig. 12] represents an approach to a cantilever transfer device, for a second transfer of the nanotube;

[0058] [Fig. 13] [Fig. 13] represents the cantilever transfer device of [Fig. 12], carrying the nanotube which has come into contact with the electrodes, for a second transfer;

[0059] [Fig. 14] [Fig. 14] illustrates the nanotube on the substrate, after second transfer;

[0060] [Fig. 15] [Fig. 15] illustrates the drastic reduction in the size of a trench, made possible by the deposition process according to the invention;

[0061] [Fig. 16] [Fig. 16] illustrates the space saved by reducing the size of the trenches;

[0062] [Fig. 17] [Fig. 17] illustrates an example of implementation of the deposition process according to the invention;

[0063] [Fig. 18] [Fig. 18] is a perspective view of an example of an embodiment of a stapling system according to the invention;

[0064] [Fig. 19] [Fig. 19] is a cutaway view of the stapling system shown in [Fig. 18];

[0065] [Fig.20] [Fig.20] is an enlarged view of the inside of the stapling system shown in Figures 18 and 19;

[0066] [Fig.21] [Fig.21] 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 process according to the invention;

[0067] [Fig.22] [Fig.22] is an enlarged perspective view of the AFM device shown in [Fig.21];

[0068] [Fig. 23] [Fig. 23] is an enlarged view of the cantilever transfer device coupled to the AFM device of [Fig. 22]; and

[0069] [Fig.24] [Fig.24] is a detailed view of the AFM device of [Fig.23]. DETAILED DESCRIPTION

[0070] We will first describe, with reference to Figures 7 and 8, an example of an embodiment of the cantilever transfer device 3. This transfer device 3 comprises two elongated blades 310, 320 separated by a piece of insulating material. These two blades 310, 320 have at one end an angled arm 31, 32 and at the other end a portion allowing attachment to a mechanical stapling device (not shown) arranged in a stapling chamber.

[0071] The cantilever transfer device 3 is intended to pick up a carbon nanotube 4 arranged on cantilevers 41;42 of a support structure 23, with reference to Figures 9 and 10.

[0072] When the arms 31 and 32 of the cantilever transfer device 3 come into contact with the nanotube 4, the latter is held in place by Van der Waals forces. The transfer device 3 can then move the nanotube towards a receiving structure, as shown in Figures 11 and 12. The cantilever transfer device 3 carrying the nanotube 4 approaches a receiving structure that accommodates an electronic chip 5 arranged between two trenches and then deposits the nanotube 4 onto the chip 5, as illustrated in Figures 13, 14, and 17.

[0073] 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 in the receiving structures, as illustrated in Figures 15 and 16. This allows the trench width to be reduced from approximately 3 mm to approximately 30 sq m. Thus, the receiving chip 5 is positioned on a protruding portion 26 between two very thin trenches. The nanotube 4 can then be deposited onto the receiving chip 5, which is positioned between two trenches 41, 42 and connected to a circuit 6 located on the receiving structure 20, as illustrated in [Fig. 16].

[0074] In the nanotube deposition process according to the invention, an intermediate fork, made by the cantilever transfer 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 growth chip. After this transfer, the nanotube is attached to the end 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 a grid electrode array. A more detailed overview of the design of the intermediate fork and the transfer processes is presented below.

[0075] The intermediate fork – or cantilever transfer device – consists of two microfabricated tines fixed to a rectangular support base. The fork and its base They can be fabricated from an insulating material such as silicon or silicon nitride (the specific material is not important) using conventional lithography and etching techniques. The tips of the teeth must be metallized and electrically connected to the blooms of the support base, either by coating 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.

[0076] The width of the fork is limited by the requirement to fit between the cantilevered pairs on the growth chip for the first transfer (approximately 30 µm). The gap between the fork teeth must be large enough to allow the outermost qubit device electrodes to fit between the teeth for the second transfer (approximately 10 µm). The teeth 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) to the normal, as illustrated in [Fig. 13]. Furthermore, the teeth need to be substantially longer than the thickness of the growth cantilevers and the depth of the trenches / wells on the qubit chip to facilitate the transfer of the nanotube. Therefore, teeth on the order of 100 to 500 µm in length are required.Finally, the teeth must be thick enough to provide a large enough surface area for the nanotube to attach to their tip during the first transfer, and therefore must be approximately 10 pm thick. This thickness also impacts the mechanical robustness of the teeth, which are designed to withstand numerous nano-assembly cycles.

[0077] The first transfer begins by optically aligning the tip of the fork above 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.

[0078] 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.

[0079] Document WO2021009290Al (Niguès et al.) discloses a force microscope atomic for evaluating a sample surface, comprising a sample holder having a first zone adapted to receive the fixedly mounted sample, a probe having a tip suitable for positioning opposite the sample surface, the microscope being configured to allow adjustment of the tip's position relative to the surface, and a support, the sample holder having at least a second zone, distinct from the first zone and fixed by with respect to the support, the sample holder being deformable so as to allow a relative displacement of the first zone with respect to the second zone, and the microscope including a detector capable of detecting a displacement of the first zone with respect to the second zone.

[0080] The document MicroMegascope (Canale et al.), 2018 [4], discloses an atomic force imaging device with a centimeter-sized oscillator. With this device, it becomes possible to obtain topographic images with nanometer-scale resolution, using a centimeter-sized tuning fork or mechanical resonator equipped with an accelerometer to measure the resonator's oscillation.

[0081] An AFM (Atomic Force Microscope) type 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 modification of the cantilever design. Indeed, in the AFM technique, the oscillator is very small and difficult to integrate into any design.

[0082] The stapling system includes, with reference to Figures 23 and 24, a fork-shaped 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-shaped probe 10, implemented as a microchip attached to the printed circuit board 100, is fixed to the end 121 of a tuning fork or mechanical resonator – inspired by the micromegoscope described in the aforementioned document [4] – which is mounted on a stack 130 of x / y / z nanopositioning motors.

[0083] The vibration of the tuning fork 200 is driven by a piezoelectric actuator 120 mounted on the top of the tuning fork 200. A MEMS accelerometer chip 122 (MEMS stands for Micro Electro Mechanical Systems), fixed to the side of the tuning fork 200 near the end, is used to detect the movement of the tuning fork 200. The fork probe 10, as attached to the end of the tuning fork 200, will transduce the interactions between its tip and the surfaces / nanotubes during the transfer process, by disturbing the vibration of the tuning fork 200.

[0084] These vibration changes 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 according to 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 comes into contact with a nanotube or a surface 20, and to avoid collisions by maintaining a safety separation between the tip of the probe 10 and the surface of the quantum circuit chip.

[0085] Of course, the present invention is not limited to the examples just described and many other configurations can be envisaged without going out of the scope of the invention.

Claims

Claims

1. Method for depositing a nano-object (4) on a receiving surface (20), characterized in that it comprises: - a first step for gripping this nano-object (4) arranged on a carrying surface (21), - a step for transferring said nano-object (4) thus gripped to the receiving surface (20), and - a step for depositing said nano-object (4) on the receiving surface (20), the implementation of a cantilever device or transfer fork (3) comprising two arms (31, 32) spaced apart each provided with a tooth, the two teeth being opposite each other and arranged to grip, hold and release said nano-object (4).

2. Deposition method according to the preceding claim, implemented for the deposition of a carbon nanotube, characterized in that the carrying surface comprises a cantilevered semiconductor chip.

3. Deposition method according to any one of the preceding claims, implemented for the deposition of nanotubes (4) on electrodes separating trenches.

4. Deposition method according to the preceding claim, characterized in that during the nanotube deposition step, the arms of the cantilever transfer device penetrate into two trenches surrounding an electrode.

5. Deposition method according to the preceding claim, characterized in that the inter-electrode trenches are less than 100 qm wide.

6. Deposition method according to any one of the preceding claims, characterized in that it further comprises a step for detecting contact of the cantilever transfer device (30) with the receiving surface (20), this detection step implementing an atomic force probe (1) comprising a tip (10) carrying the cantilever transfer device (30) and fixed to a tuning fork or mechanical resonator (11, 12) frequency-controlled around a predetermined resonance frequency.

7. Deposition method according to the preceding claim, characterized in that the detection step comprises a step for delivering information on the distance 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.

8. Deposition method according to the preceding claim, implemented for the deposition of a carbon nanotube (4) on a microelectronic circuit (20).

9. Deposition method according to the preceding claim, characterized in that the step of transferring a nano-tube (4) is arranged to deposit it on electrodes.

10. Deposition method according to any one of the preceding claims, characterized in that it is implemented in the production of a Qubit component.

11. System (10) for depositing a nano-object (4) on a receiving surface (20), implementing the deposition method according to any one of the preceding claims, characterized in that it comprises means (3) for gripping this nano-object placed on a carrying surface (21), means for transferring said nano-object thus gripped to the receiving surface (20), and means for depositing said nano-object (4) on the receiving surface (20), as said gripping, transfer and deposition means, 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 grip, hold and release said nano-object (4).

12. Deposition system (10) according to the preceding claim, characterized in that the cantilever transfer device (3) is produced in the form of two blades (310, 320) which are substantially parallel and spaced apart by an insulating part (33).

13. Deposition system (10) according to the preceding claim, characterized in that each blade (310,320) comprises an elongated part of which one cantilevered end comprises an arm substantially perpendicular to said elongated part.

14. Deposition system according to the preceding claim, characterized in that the arms comprise an electrically conductive coating.

15. Deposition system according to any one of claims 11 to 14, implemented for the deposition of nanotubes on electrodes separated by trenches.

16. Deposition system according to the preceding claim, characterized in that the inter-electrode trenches are less than 100 qm wide.

17. Deposition system according to any one of claims 11 to 16, characterized in that it is implemented in a system for stapling nanotubes on a plurality of electrodes of an electronic circuit of a quantum dot.

18. Deposition system according to any one of claims 11 to 17, characterized in that it further comprises means (1) for detecting contact or risk of contact of the cantilever transfer device (30) with the receiving surface (20), these detection means comprising an atomic force probe (1) comprising a tip (10) carrying the cantilever transfer device (30) and fixed to a tuning fork (11, 12) frequency-controlled around a predetermined resonance frequency.

19. Deposition system (2) according to the preceding claim, characterized in that the detection means further comprise means for delivering information on the difference between the tip (10) carrying the cantilever transfer device (30) and the receiving surface (20), and in that it further comprises means for controlling the transfer means from said information on said difference information.

20. Deposition system according to the preceding claim, characterized in that it is arranged in a stapling chamber within a system for producing Qubit components.

21. System for stapling carbon nanotubes in order to produce Qubit components, comprising a stapling chamber integrating a deposition system according to one of the three preceding claims.

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