TWI850407B - System and method for controlled deposition of a fluid on a substrate, use of the system and product obtained by the method - Google Patents

Abstract

The present invention relates to a system (10) for controlled deposition of a fluid on a substrate (20) and also to a method employing the system (10). The system comprises: - a nanoinjector (100), - a mechanical resonator (120) fixed to the nanoinjector (100), the mechanical resonator (120) being adapted to detect contact between the nanoinjector (100) and the substrate (20), - control means (148) of the mechanical resonator (120) comprising: ■ an excitation means (142) adapted to cause the mechanical resonator (120) to oscillate at an oscillation frequency (fi), ■ a detector means (144) adapted to detect the oscillation of the mechanical resonator (120), ■ a regulator means (146) adapted to adjust the contact between the nanoinjector (100) and the substrate (20) by controlling the oscillation of the mechanical resonator (120).

Description

System and method for controlled deposition of liquid on substrate, use of the system and products obtained by the method

The invention relates to a system for depositing a liquid in such a way as to obtain a nanolayer.

The present invention is more specifically concerned with a system for controlled deposition of a liquid on a substrate, a method for depositing a liquid on a substrate, the use of the system for additive manufacturing, and the products obtained by the method.

Additive manufacturing is a general term that covers different technologies based on layer-by-layer deposition. Two main types of additive manufacturing techniques can be distinguished: direct printing techniques and so-called indirect techniques. The former consist in depositing the desired material directly onto a substrate. Indirect techniques use an energy source such as a laser or UV lamp to act on a bath of the desired material.

Additive manufacturing is growing strongly, which is significantly changing the way industries design their manufacturing processes. There are now several additive manufacturing technologies that make it possible to obtain objects in a size range between one millimeter and one meter. Efforts are being made to go below one millimeter.

An indirect printing technique for depositing liquids known to those skilled in the art is two-photon polymerization, which enables the printing of objects on photopolymerizable resins using lasers. The resin must be transparent to the wavelength of the laser in order to be able to undergo a chemical reaction and produce polymerization. The resolution of this technique can reach half the wavelength of the laser, that is, about one hundred nanometers. The advantage of this technique is the ability to produce complex objects with high precision, especially thanks to the precision of the laser movement. However, the technology is still limited, on the one hand, by the complexity of the device, but also by the limitations of the materials used - the materials must be photopolymerizable.

Another indirect printing technique is the electron beam assisted growth technique (FEBID), which enables the deposition of materials by bombarding a precursor gas of the desired material with electrons so that the material is deposited on a substrate. This is a technique that can be mounted in a scanning electron microscope, for example. By focusing the electron beam on a point of very small size (less than 1 nm), FEBID can achieve a resolution of about one nanometer. Even though this technique is characterized by an uneven potential resolution and the possibility of producing complex objects by in situ characterization, the deposition accuracy is currently not fully achieved. In practice, the interaction between the electron beam and the volatile precursors is difficult to control, resulting in deposits whose size is generally greater than the accuracy of the focus. Furthermore, it is necessary to find a pre-driver that is suitable for the conditions of use of the device so that it can be deposited, which results in a significant reduction in the possibility of manufacturing materials.

In recent years, techniques using local probe points (AFM or STM) have made it possible to achieve resolutions approaching one hundred nanometers, as indicated in patent references WO 2017/106199 and US 2017/0259498, for example.

All of these above mentioned technologies are direct printing technologies that use the precision of movement and the spatial resolution of local probe technology to deposit liquid materials on various substrates. These technologies allow the deposition of very different materials with a wide range of solvents: - different types of polymers; - biomolecules (peptides, ADN, enzymes, ...); - various colloids.

In one case, the AFM point is used like a feather pen. It is dipped into a drop of the deposited material before each deposition. In the other case, the point is loaded with a small amount of the desired liquid material before deposition. However, both methods have a major disadvantage, even with very high resolution, since continuous printing is not possible in the absence of a reservoir with sufficient volume. Also, the precision of the deposits obtained is insufficient, since there are no parameters that can control the flow of material from or through the point.

Therefore, there is a need for additively manufactured feature layers defined by thicknesses less than 100 nm, capable of depositing multiple materials, with adjustable parameters to achieve deposition control, and sufficiently large reservoirs to uninterruptedly fabricate one or more objects.

To solve the above disadvantages or more of the above disadvantages, according to the present invention, a system for controlled deposition of a liquid on a substrate comprises: - a nano-injector, which comprises: ■ a reservoir for storing the liquid, ■ a non-deformable protrusion having an ejection orifice for extracting the liquid from the reservoir, - a mechanical resonator fixed to the nano-injector, the mechanical resonator being suitable for detecting contact between the protrusion and the substrate, - a control member of the mechanical resonator, the control member being connected to: - The excitation member of the mechanical resonator is suitable for causing the mechanical resonator to oscillate at an oscillation frequency (fi) so that the protrusion oscillates between a low position where the protrusion contacts the substrate and a high position where the protrusion does not contact the substrate, the control member is connected to a detector member suitable for detecting the oscillation of the mechanical resonator, and the control member is connected to a regulator member suitable for adjusting the contact between the protrusion and the substrate by controlling the oscillation of the mechanical resonator, the regulator member is connected to a first displacement member for adjustment, The first displacement member is at least suitable for moving the substrate of the nanojet toward or away from each other along the axis z.

In the context of the present invention, liquid means a liquid or gel that can flow under a stress value greater than its critical stress, and the liquid can or cannot contain the species in the suspension. For example, water, saline solution, vegetable oil, silicone oil, photolithography resin (SU8, etc.), ionic liquid, DNA-RNA chain, nanoparticles (colloid or other) of precious metals such as gold and silver, various biomaterials such as collagen, polysaccharides, proteins, ceramic materials such as zirconia, aluminum oxide, aluminum hydroxide, titanium dioxide can be used as liquid, provided that the size of the particles allows the liquid to pass through the ejection orifice of the nanoinjector. For example, the jet orifice may be 7 to 10 times the diameter of the particles contained in the liquid to be deposited.

For example, the species in the suspension can be colloidal species, polymer species in solution, etc.

In the context of the present invention, a substrate refers to a support that can be flat, structured or have a radius of curvature.

For example, with the structured support members, there may be support members having a square shape, a hemispherical shape, a curved shape, a sawtooth shape, a pointed shape, etc.

In the context of the present invention, a nanoinjector means an injector comprising an injection orifice having a diameter less than 1 μm.

In the context of the present invention, an ejection orifice means an orifice through which a liquid from a nano-injector is ejected for subsequent deposition on a substrate, the inner and outer diameters of the orifice being suitable for the desired deposition.

It should be noted that in addition to the inner diameter of the ejection orifice, the outer diameter also affects the deposition. In fact, the outer diameter of the ejection orifice affects the curved liquid surface formed between the protrusion and the substrate when the protrusion contacts the substrate. The ratio between the inner diameter and the outer diameter of the ejection orifice is preferably between 0.8 and 1, inclusive. If a curved liquid surface is formed when the protrusion, in particular the wall located between the inner diameter and the outer diameter of the ejection orifice, contacts the substrate, the deposition of the liquid on the substrate can be guaranteed. In addition, when the ratio between the inner diameter and the outer diameter of the ejection orifice is between 0.8 and 1, inclusive, the curved liquid surface is more stable, thereby ensuring deposition between the low and high positions of the protrusion. If the ratio between the inner diameter and the outer diameter of the ejection orifice is close to 1, that is, if the wall between the inner diameter and the outer diameter of the ejection orifice has the minimum possible thickness, it is beneficial to deposition and stability.

It should be noted that the design encompasses ejection orifices with variable sizes. Also, the ejection orifice may have a cross-section of any shape, such as square, rectangular, oval, circular, etc. For example, the protrusion and the nano-injector may be integral, such that the protrusion may then form an integral part of the nano-injector and thus be integral with the reservoir and have, for example, a conical shape. In this case, there may be a nano-capillary having a conical shape at the end, through which it is desired to deposit the liquid through the ejection orifice. It should be noted that the shape need not be conical and it is possible to have an ejection orifice with a predefined shape, for example with a desired ejection orifice diameter that can be adjusted as a function of parameters related to its design.

It should be noted that the reservoir may have a longitudinal shape, for example a cylindrical shape, with an opening at each of its ends: a first opening directly or indirectly connected to the protrusion and a second opening through which it is possible to feed the reservoir.

Furthermore, it should be noted that the reservoir and protrusion of the nano-injector are not necessarily integral and can be disassembled or disassembled so that the protrusion or reservoir of the nano-injector can be interchanged. It should also be noted that the mechanical resonator, control component, excitation component, detector component and regulator component can each be interchanged individually.

Furthermore, the protrusions can be preferably functionalized.

In the context of the present invention, a functionalized protrusion means a protrusion having an ejection orifice whose initial geometry, which depends on the geometry of the protrusion, is modified by adding elements to the protrusion. It is thus possible to adjust the inner and/or outer diameter of the ejection orifice of the protrusion in a certain way by adding elements to the protrusion, so that the geometry of the ejection orifice can be modified as desired, the functionalization being performed before the start of system operation. For example, different functionalized protrusions can be obtained by inserting nanotubes into the protrusion, one end of the nanotube protruding at the surface of the protrusion in such a way as to constitute an ejection orifice, the nanotube being fixed to the protrusion using, for example, an adhesive. The nanotubes can have different diameters and be made of carbon, boron nitride, molybdenum disulfide, silicon. For example, the nanotubes may have a length between 1 μm and 2 μm, inclusive, an outer diameter between 60 nm and 200 nm, inclusive, and an inner diameter between 5 and 50 nm, inclusive. Another example of a functionalized protrusion may be a protrusion covered with a precious material such as gold to protect the liquid from, for example, UV light.

The ejection orifice may preferably have an inner diameter between 5 and 300 nm.

In the context of the present invention, a non-deformable protrusion is understood to mean a protrusion that has stable dimensions under the conditions of use of the system during deposition.

In the context of the present invention, a mechanical resonator fixed to the nanojet means a mechanical resonator that contacts the nanojet so that the oscillation of the mechanical resonator is transmitted to the nanojet.

In the context of the present invention, a control member means a member adapted to measure, on the one hand, the difference in oscillation between the oscillation of the mechanical resonator and the set point oscillation transmitted to the mechanical resonator by the excitation member, and, on the other hand, to measure the change in oscillation caused by the contact between the protrusion and the substrate.

For example, there may be an oscilloscope as a control component, which may or may not include a proportional corrector (commonly referred to as a P corrector), an integral proportional corrector (commonly referred to as a PI corrector) or a proportional integral differential corrector (commonly referred to as a PID corrector) in a manner that improves the servo control function, causing the mechanical resonator to oscillate according to the set point oscillation.

For example, there may be piezoelectric or magnetic actuators as excitation components or there may also be acoustic actuators, such as loudspeakers.

For example, there may be devices as detector components which include, for example, accelerometers, optical fibers or electromechanical microsystems which also include lasers.

The detector component may preferably have a stiffness less than or equal to 10 ⁵ N/m, which is a function of the material from which the nanojet is constructed.

The material that makes up the nano-injector must be resistant to the liquid to be deposited. For example, if it is desired to deposit a liquid containing a strong acid such as hydrochloric acid, sulfuric acid, hydrofluoric acid, nitric acid, or phosphoric acid on a substrate containing gallium arsenide, silicon dioxide, aluminum oxide, zirconium oxide, or boron nitride, the nano-injector may be composed of a plastic material such as high-density polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, or another polyetherketone.

In the context of the present invention, a regulator member suitable for controlling the contact between a protrusion and a substrate means a member suitable for controlling the interaction force of the substrate against the protrusion when contact occurs between those two elements.

For example, there may be a component including a proportional corrector (commonly referred to as a P corrector), an integral proportional corrector (commonly referred to as a PI corrector), or a proportional integral differential corrector (commonly referred to as a PID corrector) as a regulator component.

In the context of the present invention, at least a first displacement member adapted to move the substrate closer to or further away from the nano-injector means a member adapted to move the substrate in such a way that the substrate is moved closer to or further away from the nano-injector along the axis z to control the contact between the substrate and the protrusion.

The first displacement member can be connected to a second displacement member suitable for displacing the substrate along axes x, y orthogonal to axis z to generate a pattern, the three orthogonal axes x, y and z forming a regular trihedron. Thus, the first displacement member enables the contact between the protrusion and the substrate to be adjusted, and the second displacement member enables the generation of a predefined pattern.

The first displacement member and the second displacement member are preferably included in a single displacement system.

The first displacement member and/or the second displacement member preferably comprises a piezoelectric motor having sub-nanometer resolution.

The reservoir can preferably be connected to an external reservoir. The volume of the liquid to be deposited is thus adjustable.

Another object of the present invention is a method for depositing a liquid on a substrate, the method comprising the steps of: a) obtaining a system as defined above, b) starting a controlled oscillation of the protrusion by exciting the mechanical resonator by means of the excitation member so that the mechanical resonator starts to oscillate at an oscillation frequency, the oscillation of the mechanical resonator being transmitted to the protrusion, c) moving the substrate closer to the protrusion by means of the first displacement member so as to generate a dynamic contact between the substrate and the protrusion, the protrusion being in contact with the protrusion. d) detecting the oscillation of the mechanical resonator by the detector member to observe the oscillation change when the contact occurs between the protrusion and the substrate, e) adjusting the dynamic contact between the protrusion and the substrate by means of the regulator member and in accordance with the oscillation change so as to form a curved liquid surface between the protrusion and the substrate, f) depositing liquid on the substrate through the ejection orifice during the contact between the protrusion and the substrate.

It should be noted that the system can function in a configuration where the nanoinjector is positioned vertically, i.e., where the tilt angle between the surface on which the liquid is desired to be deposited and the direction in which the nanoinjector is positioned is close to 90°.

It should be noted that according to the method of the present invention, it is possible to perform at least two of steps b), d), e) and f) simultaneously.

It should be noted that deposition may be continuous or discontinuous, discontinuous deposition may or may not be according to a predefined pattern, and may or may not be reproducible.

In the context of the present invention, dynamic contact means discontinuous or intermittent contact at the oscillation frequency of the mechanical resonator.

It should be noted that with a nanojet including a jet orifice smaller than 1 μm, it is possible to obtain deposits having a thickness between 1% and 150% of the diameter of the jet orifice, inclusive.

In the context of the present invention, control by a control element of a mechanical resonator means control consisting of analyzing at least the oscillation frequency and possibly also additional parameters related to the oscillation, such as the frequency, amplitude, phase or other excitation of the oscillation.

The distance between the low position and the high position may preferably be between 1 nm and 1 μm, inclusive.

The system may preferably further comprise the step of causing the nanojet to scan over the substrate according to a trajectory that can be modified in real time to produce the first layer (g).

It should be noted that the trajectory can be predefined to produce a desired pattern or follow any direction.

It should also be noted that the first layer can be continuous or discontinuous.

The scanning step g) can preferably be performed while maintaining a constant and predefined contact between the protrusion and the substrate.

The system may preferably further comprise a step of solidifying the first layer. This solidification step enables providing a dissolution potential and/or a degradation potential during the generation of the second layer on the first layer. This solidification step may be a subsequent step or performed in real time during the deposition. It should be noted that this step is optional, as it is possible to simply perform the deposition of a liquid that is inherently harder when extracted from the nanojet.

It should be noted that the solidification step is performed differently depending on the nature of the deposited liquid.

The nanojet scanning step g) can be preferably performed at a speed less than 40μm/s.

It should be noted that, in order to facilitate regular deposition, it is possible, for example, to reduce the sweeping speed and/or reduce the amplitude of the oscillations. Furthermore, it is also possible to use a liquid containing the dissolved species with a small particle size range, i.e. one tenth of the amplitude of the oscillations and one tenth of the desired deposition thickness.

After performing step g) of scanning with the nanojet, the system may preferably further include the following steps: h) controlling at least the contact and the oscillation frequency between the protrusion and the first layer by the control member of the mechanical resonator, i) depositing a second layer on the first layer, j) repeating the above steps h) and i) until a desired thickness is obtained.

Control step h) enables self-contact to be obtained between the protrusion and the first layer in order to prevent degradation of the first layer.

Another object of the invention concerns the use of a system as defined above for additive manufacturing.

Another object of the invention concerns a product obtained by a method as defined above, comprising one or more uniform and stable layers having a shape defined by a length greater than or equal to 1 μm.

However, in particular when using an external collector connected to the collector of the nanojet, it is possible to deposit layers with lengths much greater than 1 μm, for example layers of kilometers.

It should be noted that the minimum width of the deposited layer is the minimum width of the outer diameter of the protrusion, and may therefore be, for example, between 0.5 nm and 100 μm, inclusive, and preferably between 5 nm and 300 nm, inclusive. Furthermore, it should be noted that the height of the deposited layer decreases as the viscosity of the liquid decreases, decreases when the scanning speed of the nanojet is reduced, increases when the amplitude of the oscillation increases, and increases when the inner diameter of the protrusion increases.

For example, the maximum ratio between the thickness and width of the first layer may be approximately equal to 0.4.

The resulting product may preferably contain multiple layers.

It should be noted that the stability of the bend between the high and low positions can be improved, for example, by reducing the viscosity of the liquid; by increasing the permeability of the protrusion, that is, by increasing the ability of the liquid to flow through the protrusion under a given applied force between the reservoir and the bend; by increasing the internal cross-section of the protrusion; by increasing the affinity of the liquid for the material of the substrate and the external material of the protrusion; by using a low-frequency resonator to reduce the oscillation frequency of the protrusion and reduce the oscillation amplitude while still enabling detection.

In the context of the present invention, a given force means applying a controlled pressure to the liquid in the reservoir. For example, this forced force can be applied using compressed air, mechanically by a piston/cylinder system, or electrically by applying a voltage between the substrate and the nanojet.

Therefore, with the aid of the present invention it is possible to print in a localized manner to produce connections with nano- or micro-circuits.

1: First PID corrector, step

2: Second PID corrector, step

3': Step

3: Step

4: Step

5: Step

5': Step

6: Step

7: Step

7': Step

8: Step

9: Step

10: System

20: Substrate

100:Nanojet

102: Storage device

104: Non-deformable protrusions

108: jet orifice

120: Mechanical resonator

142: Motivational components

144: Detector components

146: Regulator components

148: Control components

160: First displacement member

f0: frequency

fi: Oscillation frequency

x:axis

y:axis

z:axis

The present invention will be better understood after reading the following description, which is given by way of example only and with reference to the following accompanying drawings, in which: [FIG. 1] represents a system according to a preferred embodiment of the present invention, [FIG. 2] represents a diagram showing the steps that can be performed to make the system according to a preferred embodiment of the present invention function.

[FIG. 1] shows a system 10 for controlled deposition of a liquid on a substrate 20.

For example, any type of liquid may be present as a liquid, such as a SU8 2002 solution, a SU 8 2010 solution, an ionic liquid, a gel or a paste.

The substrate used here is a flat substrate with a roughness of less than one nanometer.

[Figure 1] The system includes a nano-injector 100, which includes a reservoir 102 for storing liquid, and a non-deformable protrusion 104 having an injection orifice 108 for extracting liquid from the reservoir 102.

For example, it is noted that the reservoir 102 and the nano-injector 100 with nano-size can be produced by laser pulling using a Sutter Instruments P-2000 laser puller, a cylindrical shaped glass capillary tube with a length of approximately 2 cm, and a 2 mm long tapered thread. After laser pulling, the inner diameter of the capillary tube varies from 0.5 mm to a few nanometers at the apex. In this configuration, the nano-injector 100 has a tube for storing liquid. The tube has a tapered end into which a nanotube is inserted, which has an ejection orifice 108 for functionalizing the protrusion 104. The tube can then be made of glass and have an inner diameter of approximately 20 nm. The nanotubes may be carbon nanotubes that are approximately 1 μm long and have an outer diameter of approximately 20 nm and an inner diameter of approximately 1 nm.

It should be noted that in order to increase the volume of liquid available for deposition, the reservoir 102 can be connected to an external reservoir (not shown in [Figure 1]).

The system 10 further includes a mechanical resonator 120 fixed to the nanojet 100.

The mechanical resonator 120 may be in the form of a tuning fork, the body of which is twisted at its base to a block that can be moved along three spatial axes by a system of micro screws. In this configuration, the nanojet 100 is glued to the lugs of the tuning fork, for example using adhesive, so that the ejection orifice 108 is directed downwardly towards the substrate 20 positioned on the piezoelectric scanner. The body of the nanojet 100, which serves as a reservoir 102, is filled with the liquid to be deposited by means of a micro syringe, which also fills the threads by capillary action. For example, the tuning fork may comprise branches that may be made of aluminum and have a diameter approximately equal to 1 cm and a length approximately equal to 10 cm. The nanojet 100 can then be fixed to the free end of a tuning fork. The tuning fork is designed so as to be able to reproduce the same geometric shape and dimensional ratios of the various elements that make up the quartz tuning fork generally used in AFM.

It should be noted that the mechanical resonator 120 preferably has a sufficiently high quality factor to make it possible to adjust the contact at the desired frequency offset. For example, a mechanical resonator 120 with a quality factor of approximately 10,000 may be used so that the ratio between the resonant frequency and the quality factor is between 0.1 and 20, inclusive.

The system 10 further comprises a control member 148 of the mechanical resonator 120. This control member 148 enables the deposition of the liquid on the substrate 20 to be controlled.

The control member 148 is specifically connected to the excitation member 142 to excite the mechanical resonator 120 so that the mechanical resonator 120 oscillates at an oscillation frequency fi, so that the protrusion 104 oscillates between a low position where the protrusion 104 contacts the substrate 20 and a high position where the protrusion 104 does not contact the substrate 20. The control member 148 is an oscillator including the first PID corrector 1 in this embodiment. In this embodiment, there is a piezoelectric exciter as the excitation member 142. This piezoelectric exciter is bonded to the mechanical resonator 120.

The distance between the low position and the high position depends on all characteristics of the system, such as the nature of the protrusions, the liquid to be deposited, the oscillation frequency, the nature of the substrate 20 or else on the movement speed of the substrate 20.

The control member 148 is further connected to a detector member 144 which is adapted to detect the oscillations of the mechanical resonator 120 in order to read the response of the mechanical resonator 120 to the stimulus of the stimulus member 142. In this embodiment, the detector member 144 is an accelerometer which is also bonded to the mechanical resonator 120.

The control member 148 is further connected to the regulator member 146, which is suitable for adjusting the contact between the protrusion 104 and the substrate 20 by controlling the oscillation of the mechanical resonator 120.

The regulator member 146 is a second PID corrector 2 and enables the contact to be adjusted by means of a first displacement member 160, which is connected to the regulator member and is suitable for moving the substrate 20 and the nano-injector 100 closer together or further apart along the axis z. In addition, the first displacement member 160 is connected to a second displacement member suitable for moving the substrate 20 along the axes x and y, the three axes x, y and z being orthogonal and forming a regular trihedron, so that any atom can be generated on the surface of the substrate. To ensure high accuracy, the first displacement member 160 and/or the second displacement member comprise a piezoelectric motor with sub-nanometer resolution. In particular, the first displacement member 160 and the second displacement member can be part of a single displacement system. The single displacement system may be, for example, a piezoelectric scanner on which the substrate 20 is deposited. A piezoelectric scanner has a maximum travel of approximately 50 μm.

Additionally, a video camera focused on the ejection orifice 108 can be used to observe the movement of the nano-injector 100 and substrate 20 closer together.

It should be noted that in this embodiment, the tilt angle of the substrate between the moving plane of the piezoelectric scanner and the plane of the substrate is less than 5°.

Reference is made to [FIG. 2] below to indicate a method of depositing a liquid on a substrate 20 using the system shown in [FIG. 1].

In a preliminary and optional step 1 in [Figure 2], the protrusion 104 is moved closer to the substrate 20 to a distance less than 50 μm using a video camera focused on the ejection orifice 108, the video camera being focused using a micron screw of a tuning fork of a mechanical resonator 120, the distance corresponding to the maximum travel of a piezoelectric scanner which enables the two elements to be subsequently moved closer together.

In the subsequent step (step 2) in [Figure 2], the tuning fork is excited by the piezoelectric exciter so that the tuning fork vibrates at the vibration frequency fi, and the protrusion 104 begins to vibrate in a controlled manner. In this way, the vibration of the tuning fork is transmitted to the protrusion 104.

Therefore, in a further step (step 3') in [Figure 2], it is possible to measure the resonance of the system consisting of a tuning fork, a piezoelectric exciter and an accelerometer in such a way as to determine the resonance frequency of the tuning fork and its quality factor. The tuning fork is mechanically excited by the piezoelectric exciter with a resonance of a normal oscillation at a frequency f0. The oscillation is detected by an accelerometer having a resonance sensitivity of at most 0.5 nm of amplitude, which in this case corresponds to the minimum oscillation amplitude when the system is functional, i.e. to the minimum distance between the high position and the low position.

It should be noted that, for example, the piezoelectric exciter can be fed with an electrical signal whose frequency corresponds to the frequency of its mechanical excitation. The frequency of this electrical signal is adjusted by the first PID corrector 1 to control the oscillation of the tuning fork so that the response of the tuning fork detected by the accelerometer is in phase with the signal from the piezoelectric exciter, so that the tuning fork oscillates according to the oscillation of the piezoelectric exciter. The set point of this feedback loop is therefore zero phase difference between the oscillation of the piezoelectric exciter and the oscillation of the tuning fork. The tuning fork is then in phase with the piezoelectric exciter. The tuning fork is thus excited with its resonant frequency, which depends on its mechanical properties and also on the interaction with its environment.

In another step, step 3, which can be performed simultaneously with step 3' in [Figure 2], it is possible to predefine a phase shift of the set point oscillation of the second PID corrector 2, which corresponds to the phase shift induced by the predefined contact between the protrusion and the substrate 20. For example, this phase shift can be 10mHz.

Thereafter, in another step, step 4 in [FIG. 2], the substrate 20 is moved closer to the protrusion 104 by means of a piezoelectric scanner so as to generate dynamic contact between the substrate 20 and the protrusion 104. The protrusion 104 thus oscillates between a low position where it contacts the substrate 20 and a high position where it does not contact the substrate 20.

It should be noted that, at the same time, the oscillation of the tuning fork is detected by the accelerometer to observe the oscillation changes after the protrusion 104 and the substrate 20 come into contact.

Thus, after contact occurs between the protrusion 104 and the substrate 20, the force applied to the assembly consisting of the tuning fork and the nanojet 100 is modified. This modification modifies the resonant frequency and therefore the excitation frequency of the piezoelectric actuator, which is maintained at the resonant frequency of the tuning fork. For example, it is then determined that dynamic contact is achieved when the resonant frequency of the assembly consisting of the tuning fork and the nanojet 100 is modified by 10 mHz relative to the excitation frequency of the piezoelectric actuator (as selected in step 3). Thus, it is possible to verify that the system is not affected by a temporal drift of the resonant frequency before proceeding to the subsequent steps.

Thereafter, in step 5 in [FIG. 2], the dynamic contact between the protrusion 104 and the substrate 20 is adjusted by means of the second PID corrector 2 and in accordance with the oscillation in such a way that a curved liquid surface is formed between the protrusion 104 and the substrate 20. The substrate 20 is placed on a three-axis linear piezoelectric scanner with sub-nanometer motion resolution under the nanojet 100 (for example, the piezoelectric scanner used may be Tritor101 Piezosystemjena). The second PID corrector 2 controls the fine approach between the substrate 20 placed on the piezoelectric scanner and the nano-injector 100 thanks to the feedback loop until the contact between the protrusion 104 and the substrate 20 reaches the previously selected resonant frequency set point phase shift of 10mHz. The stiffness of the tuning fork enables controlled approach and prevents rapid jump-type effects when the protrusion 104 contacts the substrate 20 due to the curved liquid surface between the protrusion 104 and the substrate 20.

In another step, liquid is deposited on the substrate 20 through the ejection orifice 108 during contact between the protrusion 104 and the substrate 20.

Thereafter, in the subsequent step 6 in [FIG. 2], by moving the substrate 20 relative to the nanojet 100, the nanojet 100 is scanned on the substrate 20 along a trajectory that can be modified in real time to produce the first layer.

Thanks to the second PID corrector 2 in step 5' in [Figure 2] regulating and controlling the contact between the protrusion 104 and the substrate 20, the deposition design is generated by moving the substrate 20 while constantly maintaining the interaction with the nano-injector. Real-time detection when the interaction between the nano-injector 100 and the surface of the substrate 20 occurs makes it possible to prevent uncontrolled damage to the substrate 20 and the nano-injector 100.

The second PID corrector 2 can maintain a set point of, for example, about 10 mHz, or increase it to a few Hz, provided that the protrusion 104 resists the force of such intermittent contact with the substrate 20. The trajectory of the protrusion 104 is defined relative to the substrate 20 by electronic control of the piezoelectric scanner connected to the second PID corrector 2. The travel speed of this trajectory is also defined. Thus, scanning can be performed while maintaining a constant and predefined contact between the protrusion 104 and the substrate 20. The piezoelectric scanner then follows the set point trajectory with the help of the second PID corrector 2 and the piezoelectric scanner at a set point speed of less than 40 μm/s and maintaining a frequency deviation of 10 mHz. The limit speed to be exceeded is adjusted by the stability of the curved liquid surface during the oscillation between the low position and the high position.

In another step in [Figure 2], step 7' or 8, the first layer may be solidified. For example, when a polymerizable ink is deposited, the first layer obtained may be exposed to UV light before depositing a second layer on the first layer. This solidification step may be performed simultaneously with the deposition or thereafter.

When the deposition is completed, in another step, step 7 in [FIG. 2], the substrate 20 can be retrieved or moved away from the nanojet 100 by using a piezoelectric scanner in a manner that interrupts the contact therebetween.

Thereafter, in step 9 in [FIG. 2], the protrusion 104 may be roughly moved away from the substrate 20 using the micrometer screw of the tuning fork, and then the substrate 20 on which the first layer has been deposited may be retrieved.

In the case of such a system and using such a method, there is used: - a nano-injector comprising: a reservoir having a volume of 10 mm ³ (a cylindrical shape reservoir having a cross section approximately equal to 0.5 mm ² and a length approximately equal to 2 cm) and containing as liquid a solution of SU8 2002; and having protrusions functionalized by inserting carbon nanotubes having an inner diameter approximately equal to 50 nm and an ejection orifice approximately equal to 180 nm, - a tuning fork having a quality factor approximately equal to 1.4.10 ⁴ and oscillating at a frequency approximately equal to 1.5 kHz and causing the protrusions to oscillate between a high position and a low position, each of which positions being separated by a distance less than 10 nm, - Silicon substrate, - The substrate movement speed is about 0.125μm/s, and a regular and stable layer with a thickness of about 30nm and a width of about 150nm is obtained over a length of several microns.

Under the same conditions as described above, when the substrate movement speed is approximately equal to 0.5μm/s, a regular and stable ink layer with a thickness of approximately 5nm and a width of approximately 150nm is obtained.

Under the same conditions as indicated above, in the case of a nanoinjector in which the protrusions are functionalized by inserting a carbon nanotube having an ejection orifice with an inner diameter of about 1 nm and an outer diameter of about 20 nm, a regular and stable ink layer with a thickness of about 700 pm and a width of about 20 nm is obtained over a length of several micrometers.

In another example, used are: - a nanocapillary as a nanoinjector, comprising a reservoir having a volume of 3 mm ³ and containing a SU8 2010 solution, and having no functionalized protrusions but having an ejection orifice with an inner diameter of approximately 200 nm, - a tuning fork having a quality factor of approximately 1.4.10 ⁴ and oscillating at a frequency of approximately 1.5 kHz and causing the protrusions to oscillate between a high position and a low position, each of which is separated by a distance of approximately 1 nm, - a silicon substrate, - a movement speed of the substrate of less than 40 μm/s, a regular and stable ink layer having a thickness of approximately 35 nm and a width of approximately 200 nm is obtained over a length of a few micrometers of approximately 100 μm.

In another example, a nanoinjector is used, comprising: a reservoir having a volume of 10 mm ³ and containing an ionic solution as a liquid (for example, a solution called Bmim PF6); and having a protrusion functionalized by inserting a carbon nanotube having an ejection orifice with an inner diameter approximately equal to 60 nm and an outer diameter approximately equal to 5 nm, - a tuning fork having a quality factor approximately equal to 1.4.10 ⁴ and oscillating at a frequency approximately equal to 1.5 kHz and causing the protrusion to oscillate between a high position and a low position, each of these positions being a distance less than 50 nm away, - a silicon substrate, - The substrate movement speed is between 1 and 4 μm/s, inclusive, and a regular and stable ink layer with a thickness of approximately 0.5 nm and a width of approximately 20 nm is obtained.

By using this instance of a predefined trajectory, complex shapes such as sinusoids or spirals or circles can be generated.

Additive manufacturing can be used to produce three-dimensional ordered objects. In practice, layers can also be stacked on top of each other, the first layer on which the second layer is just deposited having previously been solidified using any solidification process. For example, approximately ten layers, each having a thickness approximately equal to 100 nm, can be stacked in succession in order to produce a stack having a circular shape and having a total thickness approximately equal to 1.5 μm high and a diameter of 8 μm.

The two layers can also be crossed in such a way that a cross-section is formed with a thickness of 300nm at the intersection, which is equal to twice the thickness of 150nm that can be a single layer, with each layer having a thickness of approximately 100nm.

The present invention has been shown and described in detail in the above description and drawings. The above description must be regarded as illustrative and is given by way of example without limiting the present invention to this single description. Many variations of embodiments are possible.

10: System

20: Substrate

100:Nanojet

102: Storage device

104: Non-deformable protrusions

108: jet orifice

120: Mechanical resonator

142: Motivational components

144: Detector components

146: Regulator components

148: Control components

160: First displacement member

Claims (17)

A system (10) for controlled deposition of a liquid on a substrate (20) comprises: a nano-injector (100) comprising: a reservoir (102) for storing the liquid, a non-deformable protrusion (104) having an ejection orifice (108) for extracting the liquid from the reservoir (102), and a mechanical resonator (120) for The nano-jet (100) is fixed to the mechanical resonator (120), the mechanical resonator (120) is suitable for detecting the contact between the protrusion (104) and the substrate (20), a control member (148) of the mechanical resonator (120), the control member is connected to: an excitation member (142) of the mechanical resonator (120), which is suitable for causing the mechanical resonator (120) to oscillate at a frequency (f i) oscillates so that the protrusion (104) oscillates between a low position where the protrusion (104) contacts the substrate (20) and a high position where the protrusion (104) does not contact the substrate (20), the control member is connected to a detector member (144) adapted to detect the oscillation of the mechanical resonator (120), and the control member is connected to a regulator member (146), It is suitable for adjusting the contact between the protrusion (104) and the substrate (20) by controlling the oscillation of the mechanical resonator (120), the regulator member (146) is connected to a first displacement member (160) for adjustment, the first displacement member is at least suitable for moving the substrate (20) of the nano-jet (100) toward each other or away from each other along an axis z. A system as claimed in claim 1, wherein the protrusion (104) is functionalized. A system as claimed in claim 1 or 2, wherein the ejection orifice (108) has an inner diameter between 5 and 300 nm, inclusive. A system as claimed in claim 1 or 2, wherein the first displacement member (160) is connected to a second displacement member suitable for displacing the substrate (20) along axes x, y orthogonal to the axis z for generating a pattern, the three orthogonal axes x, y and z forming a regular trihedron. A system as claimed in claim 4, wherein the first displacement member (160) and the second displacement member may be included in a single displacement system. A system as claimed in claim 4 or 5, wherein the first displacement member (160) and/or the second displacement member comprises a piezoelectric motor. A system as claimed in claim 1 or 2, wherein the collector (102) is connected to an external collector. A method for depositing a liquid on a substrate, the method comprising the steps of: a) obtaining a system (10) as in any one of claims 1 to 7, b) exciting the mechanical resonator (120) by the excitation member (142) so that the mechanical resonator (120) starts to oscillate at an oscillation frequency (fi) to start the controlled oscillation of the protrusion (104) The mechanical resonator (120) is vibrated, and the vibration of the mechanical resonator (120) is transmitted to the protrusion (104). c) the substrate (20) is moved closer to the protrusion (104) by means of the first displacement member (160) so as to generate dynamic contact between the substrate (20) and the protrusion (104), and the protrusion (104) contacts the substrate. d) detecting the oscillation of the mechanical resonator (120) by the detector member (144) to observe the oscillation change when contact occurs between the protrusion (104) and the substrate (20); e) using the regulator member (146) And the dynamic contact between the protrusion (104) and the substrate (20) is adjusted as the oscillations change, so as to form a curved liquid surface between the protrusion (104) and the substrate (20), and f) the liquid is deposited on the substrate (20) through the ejection orifice (108) during the contact between the protrusion (104) and the substrate (20). The method of claim 8 further comprises a step g) of causing the nanojet (100) to scan the substrate (20) along a trajectory that can be modified in real time to produce a first layer. A method as claimed in claim 9, wherein the scanning step is performed while maintaining contact between the protrusion (104) and the substrate (20) in a constant and predefined manner (g). The method of claim 9 or 10 further comprises a step of solidifying the first layer. The method of claim 9 or 10, wherein the step of sweeping the nanojet (100) is performed at a speed less than 40 μm/s (g). The method of claim 9 or 10 further comprises the following steps: h) controlling at least the contact between the protrusion (104) and the first layer and the oscillation frequency (fi) by the control member (148) of the mechanical resonator (120), i) depositing a second layer on the first layer, j) repeating the above steps h) and i) until a desired thickness is obtained. A method as claimed in any one of claims 8 to 10, wherein the distance between the low position and the high position is between 1 nm and 1 μm, including 1 nm and 1 μm. A use of a system as claimed in any one of claims 1 to 7 for additive manufacturing. A product obtained by the method of any one of claims 8 to 14, the product comprising one or more uniform and stable layers having a length greater than or equal to 1 μm. The product of claim 16 comprises a plurality of layers.