SYSTEM FOR DEFORMING AN EFFECTIVE STRUCTURE

Description

technical field

[0001] The invention relates to the technical field of engineering and the science of deformations imposed on a material.

[0002] The invention finds particular application in: the characterization operando of the deformation of the material; the fabrication of an advanced substrate or component incorporating the deformed material; the fabrication of a tunable component incorporating the deformed material, allowing the deformation of the material to be tuned during the operation of the component. State of the art

[0003] The deformation of a material can greatly affect its physical properties.

[0004] In particular, semiconductor materials undergo significant changes in their electronic band structure under deformation, which can lead to: a modification of carrier mobility; a regular modification of the band gap energy which may even lead to a transition from its indirect to direct type; a regular modification of the energy barrier of heterostructures (or even quantum wells).

[0005] These changes in their electronic properties can provide significant potential advantages.

[0006] The deformation of perovskite-type materials can modify physical properties even more dramatically, notably with phase changes leading, for example, to the appearance of ferroelectricity or ferromagnetism.

[0007] A system for deforming a useful structure, known from the prior art, comprises a diamond anvil apparatus. The apparatus comprises: the useful structure to be deformed; two anvils, made of a hard material (typically diamond, sapphire or ruby), extending on either side of the useful structure; compression means, arranged to apply a compressive force to the anvils along a compression axis.

[0008] Such a state-of-the-art system is not entirely satisfactory insofar as: (i) obtaining a tensile deformation of the useful structure, along an axis perpendicular to the compression axis, requires exerting considerable pressure on the anvils (on the order of several hundred atmospheres); (ii) the tensile deformation obtained remains very limited (for example on the order of 0.05%), despite the significant pressure exerted on the anvils; (iii) the useful structure must exhibit high mechanical resistance, capable of withstanding the high pressure.

[0009] The following document has been mentioned as a relevant illustration of the state of the art: FR 2 789 518 A1 discloses a method, and associated apparatus, for the realization of a multilayer structure with internal constraints.

[0010] The following documents are also mentioned as a further illustration of the state of the art: US 9 559 075 A1 EP 1520 669 A1 Description of the invention

[0011] The invention aims to remedy, in whole or in part, the aforementioned drawbacks. To this end, the invention relates to a system for deforming a useful structure, comprising: a stack comprising successively the useful structure and a buffer matrix; the stack having an interface between the useful structure and the buffer matrix, the interface having a mean plane; compression means, arranged to apply to the stack a compression force along the normal to the mean plane of the interface; shear means, arranged to apply to the buffer matrix longitudinal shear forces, parallel to the mean plane of the interface; the buffer matrix being adapted to transmit the shear forces to the useful structure, in the mean plane of the interface, so as to deform the useful structure. Definitions

[0012] "Deform" refers to modifying the state of stress. "State of stress" refers to the stresses resulting from internal forces acting between deformed parts of the useful structure; these internal forces can be tensile or compressive. When the internal forces are zero or nearly zero, the corresponding state of stress is called a relaxed state. "Useful structure" refers to a structure containing a material to be deformed. The useful structure can be a component. It can also be the structure from which a component will be manufactured. The component may be intended for applications in fields such as microelectronics, optics, optoelectronics, piezoelectricity, ferroelectricity, antiferroelectricity, pyroelectricity, or spintronics. "Stack" refers to a succession of elements arranged vertically.By "successively," we mean from the lowest level of the stack to the highest level of the stack. By "buffer matrix," we mean a material covering the useful structure so as to smooth out local variations in stresses acting on the useful structure during the compression of the stack. By "mean plane," we mean a 3-point reference plane on the contact surface (defining the interface between the useful structure and the buffer matrix), as defined in ASTM F534, §3.1.2, for measuring arc curvature (". bow (in English), or in the ASTM F1390 standard for measuring a curtain (" warp (in English).

[0013] Thus, unlike the prior art, such a system according to the invention makes it possible to deform a useful structure made of a brittle material to be deformed, thanks to the presence of such a buffer matrix. Indeed, the buffer matrix improves the homogeneity of the stress on the useful structure, thereby limiting the risk of breakage of the material to be deformed.

[0014] Furthermore, the shearing means allow, along an axis perpendicular to the compression axis, a deformation of the useful structure at a much higher rate than in the prior art.

[0015] Furthermore, the combined action of shear and compression means makes it possible to increase the toughness of the interface between the useful structure and the buffer matrix by reducing the risks of delamination, and by improving the efficiency of transmitting shear forces to the useful structure.

[0016] The system according to the invention may include one or more of the following characteristics.

[0017] According to one feature of the invention, the shearing means comprise a gripping element for the buffer matrix, movable in translation along a longitudinal direction, parallel to the average plane of the interface.

[0018] Thus, one advantage provided is to obtain shearing means external to the stacking that can easily be implemented in an industrial context.

[0019] According to one feature of the invention, the shearing means comprise an articulated parallelogram, arranged to move the gripping member in translation along the longitudinal direction.

[0020] Thus, one advantage provided by a four-bar mechanism (articulated together by pivot joints) is its simplicity in obtaining a translational movement.

[0021] According to one feature of the invention, the gripping member is mobile in rotation around an axis of rotation perpendicular to the average plane of the interface.

[0022] Thus, one advantage provided is the ability to control the longitudinal axis of the shear forces applied to the buffer matrix, in a plane parallel to the average plane of the interface between the useful structure and the buffer matrix.

[0023] According to one feature of the invention, the stack comprises a rubber layer; the buffer matrix being interposed between the useful structure and the rubber layer; and the shearing means comprise the rubber layer, the rubber layer being adapted to convert the compressive force into longitudinal shear forces, parallel to the mean plane of the interface, applied to the buffer matrix. Definitions

[0024] The term "layer" refers to a single layer or a plurality of sub-layers of the same type. "Rubberized" means that the layer is made of a material based on natural or synthetic rubber. "Based on" means that rubber is the main and predominant material composing the layer.

[0025] Thus, one advantage provided by the rubber layer is the ability to generate internal shear forces within the stack. The rubber layer is highly efficient at converting compressive forces (normal to the interface's mean plane) into longitudinal shear forces (parallel to the interface's mean plane). Indeed, a rubber layer possesses desirable elasticity and incompressibility properties, with a Young's modulus between 1 MPa and 100 MPa and a Poisson's ratio close to 0.5. Furthermore, the rubber layer ensures high homogeneity in the loading of the buffer matrix, thereby leading to good homogeneity in the deformation of the intended structure.

[0026] It is possible to demonstrate (see formula below) that the pressure exerted on the stack by the compression means and the thickness of the rubber layer are the two main parameters allowing adjustment of a target deformation for the useful structure: σ V ε L = ε L 32 ES 2 s L 64 3 ES 2 h + 3 s L + 4 3 1 + 2 S 2 E 1 + 3 s L 16 ES 2 h + s L 2 32 9 ES 2 h + 2 3 s L h , Or : σV is the pressure related to the compressive force exerted on the stack along the normal to the interface, εL is the isotropic biaxial strain of the useful structure / buffer matrix assembly, E is the Young's modulus of the rubber layer, h is the height of the rubber layer considered in cylindrical shape, S = πr 2 2 πrh = r 2 h , where r is the radius of the cylindrical rubber layer under consideration, s L = E L ′ t L where E'L is the biaxial elastic modulus of the useful structure / buffer matrix assembly, and tL is the thickness of the useful structure / buffer matrix assembly.

[0027] Choosing a thin rubber layer must be compensated for by applying high pressure to the stack. A thicker rubber layer reduces the pressure required for a given lateral deformation. Conversely, higher pressure promotes friction, which can be useful for preventing slippage between the buffer matrix and the load-bearing structure, or between the buffer matrix and the rubber layer.

[0028] Such internal shearing means within the stack can coexist with external shearing means, which makes it possible to consider biaxial (possibly anisotropic) deformations of the useful structure in the mean plane of the interface between the useful structure and the buffer matrix.

[0029] According to one feature of the invention, the rubber layer is made of a material selected from: a silicone-type polymer, preferably comprising polydimethylsiloxane; ethylene-vinyl acetate; a polyurethane; a polyacrylic; butadiene; a compound comprising a butyl group; an EPDM-type rubber; a fluoroelastomer, in particular a perfluoroelastomer; isoprene; a compound comprising a nitrile group; polychloroprene; styrene-butadiene. Definition

[0030] "EPDM" is the acronym for ethylene-propylene-diene monomer.

[0031] A particular advantage of polydimethylsiloxane (PDMS) is its high optical transparency in the visible and near-infrared band, which is an interesting property for optical characterization of the deformation of the useful structure.

[0032] According to one feature of the invention, the buffer matrix has a Young's modulus greater than or equal to 1 GPa.

[0033] Thus, one advantage is obtaining a resilient buffer matrix with respect to the compressive force exerted on the stack. The buffer matrix material is advantageously chosen to have a Young's modulus that matches the Young's modulus of the useful structure, so that the Young's modulus gradient is as low as possible, thereby reducing the risk of cracking in the useful structure due to local deformation inconsistencies. The quantity corresponding to the thickness multiplied by the Young's modulus is preferably chosen to be of the same order of magnitude for both the buffer matrix and the useful structure.

[0034] According to one feature of the invention, the useful structure has a strain rate at break, denoted τ R1, and the buffer matrix has a strain rate at break, denoted τ R2, satisfying τ R2 > τ R1.

[0035] Thus, one advantage provided is to protect the useful structure from cleavage or breakage during compression of the stack.

[0036] According to one feature of the invention, the buffer matrix is ​​made of a material selected from: a polymer, preferably a polyimide, polycarbonate, a polyetherimide, a polyamide-imide, polyethylene, a glass, polyetheretherketone, polypropylene, polymethyl methacrylate, polyethersulfone, polyvinyl chloride, polystyrene, polyethylene terephthalate; a ceramic, preferably SiN, SiC, Al2O3.

[0037] According to one feature of the invention, the useful structure is chosen from among: a structure based on a semiconductor-type material; a structure based on a perovskite-type material; a photonic crystal-type structure; a structure based on a composite material; a crystal; a metal; a polymer; a ceramic; a lime; a cement. Definition

[0038] By "based on", we mean that the corresponding material is the main and predominant material composing the structure.

[0039] According to one feature of the invention, the compression means comprise a lower plate and an upper plate, arranged to clamp the stack. Definition

[0040] The terms "lower" and "upper" refer to the relative position of the corresponding plates with respect to the stack (extending in a vertical direction). The lower plate is located below the stack, while the upper plate is located on top of the stack.

[0041] According to one feature of the invention, the upper plate has a non-planar contact surface with the rubber layer, the non-planar contact surface being geometrically adapted so that the rubber layer converts the compression force into longitudinal shear forces, parallel to the mean plane of the interface, applied anisotropically to the buffer matrix.

[0042] Thus, one advantage provided is to allow anisotropic biaxial deformations of the useful structure, in the average plane of the interface between the useful structure and the buffer matrix, without requiring the presence of shear means external to the stacking.

[0043] According to one feature of the invention, the stack comprises an anti-slip layer, interposed between the useful structure and the buffer matrix, the anti-slip layer having a coefficient of friction adapted to maintain the useful structure in position within the stack.

[0044] Thus, one advantage provided is to avoid a slippage of the buffer matrix on the useful structure and a direct contact of the buffer matrix on the useful structure.

[0045] According to one feature of the invention, the stack comprises a bonding film, intercalated between the useful structure and the buffer matrix.

[0046] Thus, one advantage provided is to avoid a slippage of the buffer matrix on the useful structure and a direct contact of the buffer matrix on the useful structure.

[0047] The invention also relates to a set of characteristics for a useful structure to be deformed, comprising: a system according to the invention; a characterization instrument, arranged to measure the deformation of the useful structure, the characterization instrument being preferably chosen from: a spectroscope, preferably an X-ray diffractometer, a Raman spectrometer, a photoluminescence spectroscope, a reflectance spectroscope; an instrument for measuring electrical resistivity, preferably by the four-point method or by the Van der Pauw method.

[0048] Thus, one advantage gained is the ability to obtain a characterization operando of the deformation of the useful structure, that is to say a measurement during the deformation of the useful structure.

[0049] According to one feature of the invention: the compression means comprise a lower plate and an upper plate, arranged to enclose the stack; the stack comprises: a first rubber layer, interposed between the buffer matrix and the upper plate; a second rubber layer, interposed between the lower plate and the useful structure; the stack having an additional interface between the useful structure and the second rubber layer, the additional interface having a mean plane; the shear means comprise the first rubber layer, the first rubber layer being adapted to convert the compression force into longitudinal shear forces, parallel to the mean plane of the interface, applied to the buffer matrix;The second rubber layer is adapted to convert the compressive force into longitudinal shear forces applied to the useful structure, in the mid-plane of the additional interface.

[0050] Thus, one advantage provided by such first and second rubber layers is to obtain a high rate of deformation of the useful structure along an axis perpendicular to the compression axis.

[0051] The invention also relates to an assembly for manufacturing a useful deformed structure on a supporting substrate, the manufacturing assembly comprising: a system conforming to the invention; the supporting substrate; the stack being formed on the supporting substrate.

[0052] Thus, one advantage is the ability to fabricate an advanced substrate or component incorporating the deformed material of the useful structure. Compressing the stack allows the useful structure to slide onto the substrate and bond itself in such a way as to maintain the deformation. It is also possible to obtain a tunable component incorporating the deformed material, enabling the material's deformation to be tuned during the component's operation. For example, when the useful structure is a photonic crystal, the deformation can lead to a modification of the nanostructure's period.

[0053] According to one feature of the invention, the stack includes an air layer, arranged under the useful structure, and adapted to distance the useful structure from the supporting substrate.

[0054] Thus, one advantage provided is to cancel the friction forces between the supporting substrate and the useful structure so as not to be a hindrance to the deformation of the useful structure.

[0055] According to one feature of the invention, the support substrate is air-permeable; the manufacturing assembly includes circulation means arranged to circulate an airflow from the support substrate to the air layer so that the airflow generates a lifting force maintaining the useful structure in position within the stack.

[0056] Thus, one advantage provided is to use the layer of air as an air cushion to maintain the useful structure in position within the stack.

[0057] According to one feature of the invention, the circulation means comprise a regulator, arranged to regulate the airflow circulating within the air layer.

[0058] Thus, one advantage provided is the ability to control the lifting force of the airflow.

[0059] The invention relates to a manufacturing assembly for a useful deformed structure on a supporting substrate, the manufacturing assembly comprising: a stack comprising successively the support substrate, a bonding film, the useful structure and a buffer matrix; the stack having an interface between the useful structure and the buffer matrix, the interface having a mean plane; compression means, arranged to apply to the stack a compression force along the normal to the mean plane of the interface; shear means, arranged to apply to the buffer matrix longitudinal shear forces, parallel to the mean plane of the interface; the buffer matrix being adapted to transmit the shear forces to the useful structure, in the mean plane of the interface, so as to deform the useful structure.

[0060] According to one feature of the invention, the manufacturing assembly includes a detachment layer, interposed between the bonding film and the useful structure, the detachment layer being adapted to detach the supporting substrate when the detachment layer is subjected to heat treatment.

[0061] According to one feature of the invention, the adhesive film is made of a polymer material; the manufacturing assembly comprising emission means arranged to emit electromagnetic radiation through the support substrate so as to irradiate the adhesive film, the support substrate being transparent to electromagnetic radiation. Brief description of the drawings

[0062] Other features and advantages will become apparent in the detailed description of different embodiments of the invention, the description being accompanied by examples and references to the accompanying drawings. Figure 1a is a schematic cross-sectional view of a system according to the invention for equipping a characterization assembly, before stack compression. Figure 1b is a view analogous to the figure 1a , during stack compression. Figure 2a is a view analogous to the figure 1a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 2b is a view analogous to the figure 2a , during stack compression. Figure 3a is a schematic cross-sectional view of a system according to the invention for equipping a characterization assembly, comprising shearing means external to the stack allowing tensile deformation of the useful structure. Figure 3b is a view analogous to the figure 3a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 4a is a schematic cross-sectional view of a system according to the invention for equipping a characterization assembly, illustrating the presence of shear means external to the stack allowing compression deformation of the useful structure. Figure 4b is a view analogous to the figure 4a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 5a is a schematic cross-sectional view of a characterization assembly according to the invention. Figure 5b is a view analogous to the figure 5a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 6ais a schematic cross-sectional view of a manufacturing assembly according to the invention, before stack compression. Figure 6b is a view analogous to the figure 6a , during stack compression. Figure 7a is a view analogous to the figure 6a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 7b is a view analogous to the figure 7a , during stack compression. Figure 8a is a schematic cross-sectional view of a manufacturing assembly according to the invention, comprising shearing means external to the stack allowing tensile deformation of the useful structure. Figure 8b is a view analogous to the figure 8a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 9ais a schematic cross-sectional view of a manufacturing assembly according to the invention, comprising rotary shearing means, external to the stack. Figure 9b is a view analogous to the figure 9a illustrating the presence of an anti-slip layer or a bonding film interposed between the useful structure and the buffer matrix. Figure 10 is a schematic cross-sectional view of a stack of a system according to the invention for equipping a characterization set, illustrating a useful structure composed of motifs coated with the buffer matrix. Figure 11a is a schematic cross-sectional view of a manufacturing assembly according to the invention, illustrating the presence of an air layer under the useful structure. Figure 11b is a schematic cross-sectional view of a manufacturing assembly according to the invention, illustrating the presence of an air cushion under the useful structure. Figure 12is a partial schematic perspective view of a characterization set according to the invention, illustrating a deformation of the useful structure with geometric frustration. Figure 13 is a partial schematic perspective view of a manufacturing assembly according to the invention, illustrating a deformation of the useful structure with geometric frustration. Figure 14 is a partial schematic perspective view of a system according to the invention, illustrating the presence of a rigid material embedded in the rubber layer. Figure 15a is a set of partial schematic cross-sectional views of a system according to the invention, illustrating the evolution of the deformation of the rigid material along the X-axis of the figure 14 when the useful structure is relaxed. Figure 15b is a set of partial schematic cross-sectional views of a system according to the invention, illustrating the evolution of the deformation of the rigid material along the Y-axis of the figure 14when the useful structure is relaxed. Figure 16a is a graph representing on the x-axis the compressive force applied to the stack along the normal to the interface, and on the y-axis the deformation rate of the useful structure along the X-axis of the figure 14 . Figure 16b is a graph representing on the x-axis the compressive force applied to the stack along the normal to the interface, and on the y-axis the deformation rate of the useful structure along the Y-axis of the figure 14 . Figure 17a is a schematic cross-sectional view of a manufacturing assembly according to the invention, illustrating the presence of means for emitting electromagnetic (infrared) radiation intended to interact with the bonding film (e.g. thermoplastic), to obtain a sliding interface between the useful structure and the bonding film. Figure 17b is a view analogous to the figure 17aillustrating the compression of the stack, after obtaining the sliding interface, to deform the useful structure. Figure 18a is a schematic cross-sectional view of a manufacturing assembly according to the invention, illustrating the presence of a bonding film (e.g. thermosetting) presenting a sliding interface with the useful structure. Figure 18b is a view analogous to the figure 18a illustrating the presence of means for emitting electromagnetic (ultraviolet) radiation, intended to interact with the bonding film to fix a deformed state of the useful structure. Figure 19a is a schematic cross-sectional view of a system according to the invention, illustrating the presence of a reinforcement integrated into the rubber layer, before the compression of the stack. Figure 19b is a view analogous to the figure 19a , during stack compression. Figure 20is a schematic cross-sectional view of a system according to the invention, illustrating a top plate having a non-planar surface, and a rubber layer surmounted by a polymer layer having a non-planar surface.

[0063] It should be noted that the drawings described above are schematic and are not necessarily to scale for the sake of readability and to simplify understanding. The cross-sections are made along the normal to the mean plane of the interface between the useful structure and the buffer matrix. Detailed description of the implementation methods

[0064] Identical elements or elements performing the same function will bear the same references for the different embodiments, for the sake of simplification. System

[0065] An object of the invention is a system for deforming a useful structure 1, comprising: a stack comprising successively the useful structure 1 and a buffer matrix 2; the stack having an interface between the useful structure 1 and the buffer matrix 2, the interface having a mean plane; compression means, arranged to apply to the stack a compression force F along the normal Z'-Z to the mean plane of the interface; shear means, arranged to apply to the buffer matrix 2 longitudinal shear forces f, parallel to the mean plane of the interface; the buffer matrix 2 being adapted to transmit the shear forces f to the useful structure 1, in the mean plane of the interface, so as to deform the useful structure 1.

[0066] The elongation δR (or shortening) of the useful structure 1 relative to its initial length R0 along a longitudinal axis of the shear forces f is illustrated in figures 1b, 2b , 6b and 7b . Stacking

[0067] The useful structure 1 has a strain rate at break, denoted τR1. The useful structure 1 can be chosen from: a structure based on a semiconductor-type material; a structure based on a perovskite-type material; a photonic crystal-type structure; a structure based on a composite material; a crystal; a metal; a polymer; a ceramic; a lime; a cement.

[0068] The material to be deformed in the useful structure 1 is solid. By way of non-limiting examples, the useful structure 1 can be in the form of a thin or thick film, or a patterned film (as illustrated in the Figure 10), of a network of nanometric wires, of a two-dimensional material, referred to as 2D, comprising one to a few atomic monolayers. An advantage provided by a pattern-structured film is that it increases the elastic strain limit. Indeed, the elastic strain limit of a structure depends on its geometry. The cross-sectional area (the surface of the cross-section normal to the Z'-Z axis of the compressive force F) varies inversely with the elastic strain limit. The useful structure 1 advantageously has a geometry compatible with microtechnologies / nanotechnologies. In other words, the useful structure 1 can have a thickness ranging from a few nm to a few µm. By "thickness," we mean the dimension along the normal Z'-Z to the mean plane of the interface between the useful structure 1 and the buffer matrix 2. However, the useful structure 1 can be macroscopic.When the useful structure 1 is macroscopic, its surface area can be several tens of cm². As a non-limiting example, the useful structure 1 can be a silicon layer with a thickness between 200 nm and 2 µm.

[0069] Buffer matrix 2 advantageously has a Young's modulus greater than or equal to 1 GPa. Buffer matrix 2 has a strain rate at break, denoted τR2, advantageously satisfying τR2 > τR1. Buffer matrix 2 is advantageously made of a material selected from: a polymer, preferably a polyimide, polycarbonate, a polyetherimide, a polyamide-imide, polyethylene, a glass, polyetheretherketone, polypropylene, polymethyl methacrylate, polyethersulfone, polyvinyl chloride, polystyrene, polyethylene terephthalate; a ceramic, preferably SiN, SiC, Al2O3.

[0070] The stacking advantageously comprises a rubber layer 3; the buffer matrix 2 being interposed between the useful structure 1 and the rubber layer 3. The rubber layer 3 is advantageously made of a material selected from: a silicone-type polymer, preferably comprising polydimethylsiloxane (PDMS); ethylene-vinyl acetate; a polyurethane; a polyacrylic; butadiene; a compound comprising a butyl group; an EPDM-type rubber; a fluoroelastomer, in particular a perfluoroelastomer; isoprene; a compound comprising a nitrile group; polychloroprene; styrene-butadiene.

[0071] When the buffer matrix 2 is a polyimide film and the rubber layer 3 is made of PDMS, the rubber layer 3 can be bonded to the buffer matrix 2 using the single reagent 3-mercaptopropyltrimethoxysilane (MPTMS) at room temperature. When the useful structure 1 is a silicon layer, the polyimide film can be bonded to the useful structure 1 using an adhesive (e.g., HD3007 or HD3008 marketed by HD Microsystems™).

[0072] As illustrated in the figure 14 and to figures 15a and 15b The stack may include a rigid material 30 embedded in the rubber layer 3. "Rigid" means that the rigid material 30 has a Young's modulus greater than or equal to 100 MPa, preferably greater than or equal to 1 GPa. The rigid material 30 is geometrically adapted to exhibit differentiated tensile strength along the X and Y axes, as illustrated in figures 16a and 16b, starting from a threshold of compressive force F applied to the stack along the normal Z'-Z to the mean plane of the interface. Indeed, as illustrated in the figure 16a From the compressive force threshold F, the tensile strength along the X-axis corresponds to the sum of the coefficients α and β, while the tensile strength along the Y-axis corresponds to the coefficient β, as illustrated in the figure 16bBy way of non-limiting example, the rigid material 30 can be a polymer, preferably a polyimide, when the rubber layer 3 is made of PDMS. When the useful structure 1 is compressed vertically, the resulting lateral deformation differs along each of the X and Y axes due to the geometry of the corrugations in the rigid material 30. The corrugated rigid material 30 does not change the tensile strength along the X axis as long as the rigid material 30 is not "unfolded," whereas the rigid material 30 offers tensile strength along the Y axis independently of its corrugation. Above a certain compression ratio, the corrugations in the rigid material 30 disappear. The tensile strength becomes comparable along both the X and Y axes. As illustrated in figures 16a and 16bThe deformation is initially rapid along the X axis since, along this axis, the rigid material 30 unfolds without offering resistance. As soon as the rigid material 30 is unfolded under the effect of vertical pressure, its resistance appears along the X axis. The slope then becomes identical to that describing the variation along the Y axis, where the resistance to deformation is not related to the presence or state of the undulations.

[0073] As illustrated in figures 19a and 19bThe stack may include a reinforcement 31, made of a rigid material, and integrated into the rubber layer 3, for example by molding. The reinforcement 31 may have a Young's modulus on the order of 1 GPa. The reinforcement 31 may have a thickness of a few hundred µm. The reinforcement 31 has a non-planar surface. The reinforcement 31 may have a different profile along the axes defining a plane parallel to the mean plane of the interface between the useful structure 1 and the buffer matrix 2. Under the action of the compressive force F, the reinforcement 31 flattens in such a way as to promote tensile deformation of the buffer matrix 2 and thereby of the useful structure 1. The reinforcement 31 may have a variable thickness (i.e., dimension along the normal to the mean plane of the interface between the buffer matrix 2 and the useful structure 1) so as to allow for non-uniform deformation.

[0074] As illustrated in figures 2a, 2b , 3b , 4b , 5b, 7a, 7b , 8b And 9b The stack may include an anti-slip layer 4, interposed between the useful structure 1 and the buffer matrix 2, the anti-slip layer 4 having a coefficient of friction suitable for maintaining the useful structure 1 in position within the stack. Alternatively, the stack may include an adhesive film 4', interposed between the useful structure 1 and the buffer matrix 2. Compression methods

[0075] The compression means may include a lower plate 5a and an upper plate 5b, arranged to clamp the stack.

[0076] The lower plate 5a and upper plate 5b are rigid. By "rigid", we mean that the lower plate 5a and upper plate 5b have a Young's modulus greater than or equal to 100 MPa, preferably greater than or equal to 1 GPa.

[0077] As illustrated in Figures 12 And 13, the upper plate 5b may have a non-planar contact surface with the rubber layer 3, the non-planar contact surface being geometrically adapted so that the rubber layer 3 converts the compressive force F into longitudinal shear forces f, parallel to the mean plane of the interface, applied anisotropically to the buffer matrix 2. This is referred to as deformation of the useful structure 1 with geometric frustration.

[0078] As illustrated in the Figure 20The rubber layer 3 can be surmounted by a polymer layer 32 having a non-planar surface 320. The upper plate 5b can have a non-planar surface 51, intended to be in contact with the polymer layer 32. The non-planar surface 320 of the polymer layer 32 can have a different shape from the non-planar surface 51 of the upper plate 5b. The different shapes of the non-planar surface 51 of the upper plate 5b and the non-planar surface 320 of the polymer layer 32 can be adapted to obtain an asymmetry in the resulting deformation, which can be, for example, uniaxial, compressive about one axis, or tensile about another axis. The polymer layer 32, formed on the rubber layer 3, has a Young's modulus strictly greater than the Young's modulus of the rubber layer 3.

[0079] As illustrated in figures 8a, 8b , 9a and 9b, the lower plate 5a can be made in the form of a chassis adapted to receive the stacking. Shearing methods

[0080] As illustrated in figures 3a, 3b , 4a, 4b , 8a, 8b , 9a and 9b The shearing means may include a gripping member 6 of the buffer matrix 2, movable in translation along a longitudinal direction parallel to the mean plane of the interface. The shearing means advantageously include an articulated parallelogram, arranged to move the gripping member 6 in translation along the longitudinal direction. The gripping member 6 is advantageously movable in rotation about an axis of rotation ω perpendicular to the mean plane of the interface. The gripping member 6 may include two gripping arms 60, arranged at the lateral ends of the buffer layer 2. As illustrated in figures 8a, 8b , 9a and 9bThe gripping element 6 can be mounted on a frame 5a. Advantageously, the frame 5a is rotatable about an axis of rotation ω perpendicular to the mid-plane of the interface. It is then possible to deform the useful structure 1 using the centrifugal force generated by the rotation. Adding weights to the periphery of the buffer matrix 2 further increases the centrifugal force. Such shearing means are external to the stack.

[0081] The shear means advantageously include the rubber layer 3, the rubber layer 3 being adapted to convert the compressive force F into longitudinal shear forces f, parallel to the mean plane of the interface, applied to the buffer matrix 2. Such shear means are internal to the stack, and can coexist with shear means external to the stack, which makes it possible to consider biaxial (possibly anisotropic) deformations of the useful structure 1 in the mean plane of the interface between the useful structure 1 and the buffer matrix 2. It is also possible to use only shear means internal to the stack, and to do without shear means external to the stack.

[0082] The shearing means may include a rigid structure arranged around the rubber layer 3 to control the deformation of the rubber layer 3. More specifically, the rigid structure is geometrically adapted to control the deformation of the rubber layer 3 in a plane parallel to the mean plane of the interface, during the conversion of the compressive force F into longitudinal shear forces f, parallel to the mean plane of the interface, applied to the buffer matrix 2. Such a rigid structure prevents, in certain directions, biaxial deformations of the useful structure 1 in the mean plane of the interface between the useful structure 1 and the buffer matrix 2. By way of non-limiting example, the rigid structure may be made using a mold. By "rigid," it is understood that the rigid structure has a Young's modulus greater than or equal to 100 MPa, preferably greater than or equal to 1 GPa. Additional equipment

[0083] The system may include an enclosure adapted to house the stack. The enclosure may have walls adapted to allow access to the compression means, and where applicable, to the shear means external to the stack, so that they can be actuated. Such an enclosure allows the stack to undergo heat treatment (e.g., an oven function), for example, to obtain a specific operating point of the useful structure 1. By way of illustration, the electrical conductivity of the useful structure 1 can vary as a function of temperature.

[0084] The system advantageously includes fixed side walls arranged to laterally enclose the rubber layer 3. Such side walls can be part of a mold. These side walls allow for control of the lateral deformation of the rubber layer 3. This is referred to as frustrated deformation. It is also possible to provide a lubricant between the side walls and the stack. Characterization set

[0085] As illustrated in figures 5a and 5b An object of the invention is a set of characteristics of a useful structure 1 to be deformed, comprising: a system according to the invention; a characterization instrument 7, arranged to measure the deformation of the useful structure 1, the characterization instrument 7 being preferably chosen from: a spectroscope, preferably an X-ray diffractometer, a Raman spectrometer, a photoluminescence spectroscope, a reflectance spectroscope; an instrument for measuring electrical resistivity, preferably by the four-point method or by the Van der Pauw method.

[0086] Other spectrometry techniques are possible: optical absorption, X-ray absorption, etc.

[0087] According to one embodiment: the compression means comprise a lower plate 5a and an upper plate 5b, arranged to enclose the stack; the stack comprises: a first rubber layer 3, interposed between the buffer matrix 2 and the upper plate 5b; a second rubber layer 3', interposed between the lower plate 5a and the useful structure 1; the stack having an additional interface between the useful structure 1 and the second rubber layer 3', the additional interface having a mean plane; the shear means comprise the first rubber layer 3, the first rubber layer 3 being adapted to convert the compression force F into longitudinal shear forces f, parallel to the mean plane of the interface, applied to the buffer matrix 2;the second rubber layer 3' is adapted to convert the compressive force F into longitudinal shear forces f applied to the useful structure 1, in the mean plane of the additional interface. ;

[0088] By way of non-limiting examples, the upper plate 5b can be made of polymethyl methacrylate (PMMA), and the lower plate 5a can be made of a metallic material such as Al. PMMA is advantageous in terms of rigidity and transparency (particularly in the visible range). As illustrated in figures 5a and 5b , the compression means may include two clamping screws 50 whose tightening torque can be measured using a torque screwdriver.

[0089] The first and second rubber layers 3, 3' are advantageously made of a material selected from: a silicone-type polymer, preferably comprising polydimethylsiloxane (PDMS); ethylene-vinyl acetate; a polyurethane; a polyacrylic; butadiene; a compound comprising a butyl group; an EPDM-type rubber; a fluoroelastomer, in particular a perfluoroelastomer; isoprene; a compound comprising a nitrile group; polychloroprene; styrene-butadiene.

[0090] When the first and second rubber layers 3, 3' are made of PDMS, it is not necessary to bond them respectively to the upper plate 5b and lower plate 5a. Indeed, PDMS, due to its low Young's modulus, has a very high coefficient of friction.

[0091] As illustrated in the figure 12, the lower plate 5a may have a non-planar contact surface with the second rubber layer 3', the non-planar contact surface being geometrically adapted so that the second rubber layer 3' converts the compression force F into longitudinal shear forces f, applied anisotropically to the useful structure 1, in the mean plane of the additional interface. Manufacturing Set #1

[0092] As illustrated in figures 6a, 6b, 7a, 7b , 8a, 8b , 9a, 9b , 11a And 11b An object of the invention is a manufacturing assembly for a useful structure 1 deformed on a support substrate S, the manufacturing assembly comprising: a system conforming to the invention; the supporting substrate S; the stack being formed on the support substrate S.

[0093] By way of non-limiting examples, the support substrate S can be made of a material chosen from Si, Ge, Al 2 O 3 (sapphire), a glass.

[0094] As illustrated in figures 11a And 11b The stack may include an air layer 8, arranged under the useful structure 1, and adapted to distance the useful structure 1 from the support substrate S. The gripping element 6 of the buffer matrix 2 advantageously extends over the lateral edges of the stack so as to delimit the air layer 8. After deformation of the useful structure 1, the air can be removed from the air layer 8, for example by means of vacuuming, in order to obtain adhesion of the stack to the support substrate S.

[0095] According to an embodiment illustrated in the figure 11bThe support substrate S is air-permeable, and the fabrication assembly includes circulation means arranged to circulate an airflow from the support substrate S to the air layer 8 such that the airflow generates a lifting force maintaining the useful structure 1 in position within the stack. The circulation means advantageously include a regulator arranged to regulate the airflow circulating within the air layer 8. The regulator may include an air compressor.

[0096] As an alternative to the air layer 8, the support substrate S may include a temporary bonding film on which the stack is formed. The temporary bonding film may be made of a material whose phase change can be controlled. The temporary bonding film may undergo suitable heat treatment to prevent permanent bonding and allow longitudinal sliding (in the mid-plane of the interface between the temporary bonding film and the useful structure 1) of the useful structure 1.

[0097] In this respect, the manufacturing assembly may include an enclosure adapted to house the system and the support substrate S. The enclosure may have walls adapted to allow access to the compression means, and where applicable, to the shear means external to the stack, so that they can be actuated. Such an enclosure notably allows for the application of a heat treatment to the temporary bonding film (e.g., a thermoplastic polyimide), the heat treatment being adapted to modify the mechanical properties of the temporary bonding film so as to allow longitudinal sliding of the useful structure 1 to deform it. Lowering the temperature of the heat treatment allows the temporary bonding film to re-polymerize and fixes the deformed state of the useful structure 1. According to an alternative embodiment, a heat treatment (e.g.(at a temperature between 80°C and 120°C) is applied to the substrate support S and the temporary adhesive film to limit the adhesion energy between the useful structure 1 and the temporary adhesive film, thereby creating a sliding interface between the useful structure 1 and the temporary adhesive film. When the useful structure 1 is deformed, the bond between the useful structure 1 and the temporary adhesive film is optimized, either by cooling the assembly to room temperature (direct bonding) or by heating the assembly to 300°C while applying bonding pressure (thermocompression).

[0098] After the useful structure 1 is deformed on the support substrate S, the elements covering the useful structure (e.g., anti-slip layer 4, buffer matrix 2, rubber layer 3) can be removed to expose the useful structure 1. The deformed useful structure 1 can then be transferred to a final substrate, for example, via oxide-oxide bonding (e.g., SiO₂), possibly with the use of a plasma (e.g., O₂, O₂). The support substrate S is then removed to complete the transfer of the deformed useful structure 1. Manufacturing Set #2

[0099] As illustrated in figures 17a, 17b , 18a, 18b An object of the invention is a manufacturing assembly for a useful structure 1 deformed on a support substrate S, the manufacturing assembly comprising: a stack comprising successively the support substrate S, a bonding film FC, the useful structure 1 and a buffer matrix 2; the stack having an interface between the useful structure 1 and the buffer matrix 2, the interface having a mean plane; compression means, arranged to apply to the stack a compression force F along the normal Z'-Z to the mean plane of the interface; shear means, arranged to apply to the buffer matrix 2 longitudinal shear forces f, parallel to the mean plane of the interface; the buffer matrix 2 being adapted to transmit the shear forces f to the useful structure 1, in the mean plane of the interface, so as to deform the useful structure 1.

[0100] Stacking can be obtained from a SoP-type support substrate S (“ Semiconductor-on-Polymer(in English), on which the buffer matrix 2 is formed. The semiconducting layer 2 of the SoP-type support substrate S forms the useful structure 1. The polymer layer of the SoP-type support substrate S forms the FC bonding film.

[0101] The stacking may include a 4' bonding film, inserted between the useful structure 1 and the buffer matrix 2, having an anti-slip function.

[0102] The compression means may include a lower plate 5a and an upper plate 5b, arranged to clamp the stack.

[0103] The manufacturing assembly may include a detachment layer CD, interposed between the bonding film FC and the useful structure 1. The detachment layer CD is adapted to detach the support substrate S when the detachment layer CD is subjected to heat treatment. By way of non-limiting example, the detachment layer CD may be made of a thermoplastic material. Alternatively, the bonding film FC inherently possesses a detachment function.

[0104] The FC bonding film is advantageously made of a polymer material. The manufacturing assembly may include emission means 9, arranged to emit electromagnetic radiation 90 through the support substrate S so as to irradiate the FC bonding film, the support substrate S being transparent to electromagnetic radiation 90. By way of non-limiting example, the support substrate S may be made of glass or sapphire.

[0105] In one embodiment, the FC bonding film is made of a thermoplastic polymer (e.g., a polyimide), and the emission means 9 are adapted to emit infrared electromagnetic radiation 90, the wavelength of which can be on the order of 1 µm. The thermoplastic polymer is opaque to infrared radiation. This embodiment makes it possible to obtain so-called "cold wall" heating of the FC bonding film. The electromagnetic radiation 90 passes through the infrared-transparent materials of the stack and heats the infrared-opaque materials of the stack in a targeted manner. The emission means may include an infrared lamp 9, arranged under the lower plate 5a. The emission means 9 are deactivated in order to freeze the deformed state of the useful structure 1.

[0106] In one embodiment, the FC bonding film is made of a thermosetting polymer (e.g., an epoxy resin), and the emission means 9 are adapted to emit ultraviolet electromagnetic radiation 90. The ultraviolet electromagnetic radiation 90 is activated to polymerize the FC bonding film in order to fix the deformed state of the useful structure 1.

[0107] The invention is defined by the attached set of claims.

Claims

1. A system for deforming an effective structure (1), including: - a stack comprising successively the effective structure (1) and a buffer matrix (2), the stack having an interface between the effective structure (1) and the buffer matrix (2), the interface having a mean plane; - compression means designed to apply a compressive force (F) to the stack along an axis (Z'-Z) normal to the mean plane of interface; - shear means designed to apply to the buffer matrix (2) longitudinal shear forces (f) parallel to the mean plane of the interface; the buffer matrix (2) being designed to transmit the shear forces (f) to the effective structure (1) in the mean plane of the interface so as to deform the effective structure (1).

2. The system as claimed in claim 1, in which the shear means include a member (6) for holding the buffer matrix (2) mobile in translation in a longitudinal direction parallel to the mean plane of the interface.

3. The system as claimed in claim 2, in which the shear means include an articulated parallelogram designed to move the holding member (6) in translation in the longitudinal direction.

4. The system as claimed in claim 2 or 3, in which the holding member (6) is mobile in rotation about a rotation axis (ω) perpendicular to the mean plane of the interface.

5. The system as claimed in any one of claims 1 to 4, in which the stack includes a rubbery layer (3), the buffer matrix (2) being between the effective structure (1) and the rubbery layer (3), and the shear means include the rubbery layer (3), the rubbery layer (3) being designed to convert the compression force (F) into longitudinal shear forces (f) parallel to the mean plane of the interface applied to the buffer matrix (2).

6. The system as claimed in claim 5, in which the rubbery layer (3) is made of a material chosen from: - a silicone-type polymer preferably including polydimethylsiloxane (PDMS); - vinyl ethylene acetate; - polyurethane; - polyacrylic; - butadiene; - a compound including a butyl group; - a rubber of EPDM type; - a fluoroelastomer, in particular a perfluoroelastomer; - isoprene; - a compound including a nitrile group; - polychloroprene; - styrene-butadiene.

7. The system as claimed in any one of claims 1 to 6, in which the buffer matrix (2) has a Young's modulus greater than or equal to 1 GPa.

8. The system as claimed in any one of claims 1 to 7, in which the effective structure (1) has a deformation rate at rupture denoted τR1 and the buffer matrix (2) has a deformation rate at rupture denoted τR2 satisfying the condition τR2 > τR1.

9. The system as claimed in any one of claim 1 to 8, in which the buffer matrix (2) is made of a material chosen from: - a polymer, preferably a polyimide, polycarbonate, polyetherimide, polyamide-imide, polyethylene, glass, polyetheretherketone, polypropylene, polymethylmethacrylate, polyethersulfone, polyvinyl chloride, polystyrene, polyethylene terephthalate; - a ceramic, preferably SiN, SiC, Al2O3.

10. The system as claimed in any one of claims 1 to 9, in which the effective structure (1) is chosen from: - a structure based on a semiconductor type material; - a structure based on a perovskite type material; - a photonic crystal type structure; - a structure based on a composite material; - a crystal; - a metal; - a polymer; - a ceramic; - chalk; - cement.

11. The system as claimed in any one of claims 1 to 10, in which the compression means include a lower plate (5a) and an upper plate (5b) designed to fit tightly around the stack.

12. The system as claimed in claim 11 in combination with claim 5 or 6, in which the upper plate (5b) has a non-plane surface in contact with the rubbery layer (3), the non-plane contact surface being geometrically designed so that the rubbery layer (3) converts the compression force (F) into longitudinal shear forces (f) parallel to the mean plane of the interface applied anisotropically to the buffer matrix (2).

13. The system as claimed in any one of claims 1 to 12, in which the stack includes an anti-sliding layer (4) between the effective structure (1) and the buffer matrix (2), the anti-sliding layer (4) having a coefficient of friction designed to hold the effective structure (1) in position in the stack.

14. The system as claimed in any one of claims 1 to 12, in which the stack includes a bonding film (4') between the effective structure (1) and the buffer matrix (2).

15. An assembly for characterization of an effective structure (1) to be deformed, including: - a system in accordance with the invention according to any one of claims 1 to 14; - a characterization instrument (7) designed to measure the deformation of the effective structure (1), the characterization instrument (7) preferably being chosen from: a spectroscope, preferably an X-ray diffractometer, a Raman spectrometer, a photoluminescence spectroscope, a reflectance spectroscope; an instrument for measuring electrical resistivity, preferably by the four point method or by the Van der Pauw method.

16. The characterization assembly as claimed in claim 15, in which: - the compression means include a lower plate (5a) and an upper plate (5b) designed to fit tightly around the stack; - the stack includes: a first rubbery layer (3) between the buffer matrix (2) and the upper plate (5b); a second rubbery layer (3') between the lower plate (5a) and the effective structure (1); the stack having an additional interface between the effective structure (1) and the second rubbery layer (3'), the additional interface having a mean plane; - the shear means include the first rubbery layer (3), the first rubbery layer (3) being designed to convert the compression force (F) into longitudinal shear forces (f) parallel to the mean plane of the interface applied to the buffer matrix (2); - the second rubbery layer (3') is designed to convert the compression force (F) into longitudinal shear forces (f) applied to the effective structure (1) in the mean plane of the additional interface.

17. An assembly for fabrication of a deformed effective structure (1) on a support substrate (S), the fabrication assembly including: - a system as claimed in any one of claims 1 to 14; - the support substrate (S); the stack being formed on the support substrate (S).

18. The fabrication assembly as claimed in claim 17, in which the stack includes a layer (8) of air below the effective structure (1) designed to space the effective structure (1) from the support substrate (S).

19. The fabrication assembly as claimed in claim 18, in which the support substrate (S) is permeable to air, the fabrication assembly including circulation means designed to cause a flow of air to circulate from the support substrate (S) toward the layer (8) of air so that the flow of air generates a sustentation force holding the effective structure (1) in position in the stack.

20. The fabrication assembly as claimed in claim 19, in which the circulation means include a regulator designed to regulate the flow of air circulating in the layer (8) of air.

21. An assembly for fabrication of a deformed effective structure (1) on a support substrate (S), the fabrication assembly including: - a stack comprising successively the support substrate (S), a bonding film (FC), the effective structure (1) and a buffer matrix (2), the stack having an interface between the effective structure (1) and the buffer matrix (2), the interface having a mean plane; - compression means designed to apply a compressive force (F) to the stack along an axis (Z'-Z) normal to the mean plane of interface; - shear means designed to apply to the buffer matrix (2) longitudinal shear forces (f) parallel to the mean plane of the interface; the buffer matrix (2) being designed to transmit the shear forces (f) to the effective structure (1) in the mean plane of the interface so as to deform the effective structure (1).

22. The fabrication assembly as claimed in claim 21, including a detachment layer between the bonding film (FC) and the effective structure (1), the detachment layer being designed to detach the support substrate (S) when the detachment layer is subjected to a heat treatment.

23. The fabrication assembly as claimed in claim 21 or 22, in which the bonding film (FC) is made of a polymer material, the fabrication assembly including emission means (9) designed to emit electromagnetic radiation (90) through the support substrate (S) in such a manner as to irradiate the bonding film (FC), the support substrate (S) being transparent to the electromagnetic radiation (90).