Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/185—Joining of semiconductor bodies for junction formation
  • H01L21/187—Joining of semiconductor bodies for junction formation by direct bonding
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02002—Preparing wafers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
  • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
  • H01L21/7806—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices involving the separation of the active layers from a substrate

Definitions

• the present invention relates to the field of thin film transfer for microelectronic, optical, microsystems, etc. applications. It relates in particular to a removable structure that can be used for the transfer or handling of thin layers.
• Some transfer methods consist of assembling the thin film (placed on the initial substrate) and the target substrate, then mechanically and / or chemically removing the initial substrate, thereby transferring the layer to the target substrate.
• the main drawbacks of this approach are the costs associated with the loss of the initial substrate and the restrictive mechanical and chemical treatments liable to degrade the quality of the thin film during the transfer.
• a difficulty associated with these approaches is that the detachment can sometimes be done at the level of interfaces or layers other than the weakened one because the mechanical stress and / or the chemical attack can hardly be localized precisely at the level of said weakened layer or interface. .
• the variability of the geometry of the edges of the substrates, the method of applying the mechanical stress or the chemical etching solution for the dismantling can induce the start of the separation at an interface other than the weakened one, even if this other interface has a mechanical strength greater than the strength of the weakened interface.
• these arrangements do not always make it possible to prevent the initiation of separation at a non-target interface.
• Document FR2995446 addresses removable structures comprising at least two interfaces, including the weakened one at which separation is expected. It offers solutions for redirecting the separation front towards the weakened interface when the latter starts at the level of the other interface.
• the present invention relates to an alternative solution helping to localize the detachment at the weakened interface of a removable structure.
• An object of the invention is a removable structure comprising at least two interfaces, one of which is the weakened interface or the privileged detachment interface. Said removable structure is used for the transfer or handling of layers.
• the present invention relates to a removable structure for transferring or handling layers, comprising:
• a donor substrate comprising a useful layer to be transferred placed on an initial substrate
• the privileged detachment interface being located between said useful layer and the initial substrate
• the assembly interface being located between said useful layer and the recipient substrate .
• the removable structure is remarkable in that the assembly interface has an assembly interruption zone comprising at least one cavity present in the receiving substrate or in the useful layer, in the latter case, the depth of the cavity being strictly less than the thickness of the useful layer.
• the assembly interruption zone is located in a peripheral region of the dismountable structure, it makes it possible to modify a stress field at the head of the front of a separation wave when the latter is initiated in the assembly interface to the transfer or manipulation of the useful layer.
• the modification of the stress field by the -at least one- cavity of the assembly interruption zone allows the deviation of the separation wave, from the assembly interface to the privileged detachment interface, thus allowing a transfer of the useful layer on the receiving substrate.
• the assembly interruption zone extends over a length, along the perimeter of the removable structure, less than or equal to 20mm;
• the assembly interruption zone is located less than 10mm from the edges of the dismantling structure
• the (at least one) cavity has lateral dimensions of between a few microns and a few millimeters, preferably between 20 microns and 1mm; • the (at least one) cavity has a depth of between 0.5 microns and several tens of microns, typically 50 microns;
• the (at least one) cavity has, in a plane parallel to the assembly interface, a square, rectangular, triangular, trapezoidal or rounded periphery;
• At least one rectilinear segment of the perimeter of the (at least one) cavity is parallel to a dismantling edge of the removable structure or to the tangent to a dismantling edge of the removable structure;
• a rectilinear segment of the perimeter of the (at least one) cavity which has the largest lateral dimension, is parallel to a dismantling edge of the removable structure or to a tangent to a dismantling edge of the dismantled structure;
• the assembly interruption zone comprises a plurality of cavities spaced apart by a distance of between 1 micron and 1mm, typically between a few microns and a few hundred microns;
• the cavities are aligned along a straight line or along a curved line, the convexity of which is oriented towards the center of the removable structure;
• the assembly interruption zone is positioned less than 8mm from the edges of the removable structure, or even less than 3mm;
• the useful layer has a thickness between a few hundred nanometers and several hundred microns, typically between 200 nm and 200 microns;
• the privileged detachment interface presents a first interfacial energy
• the assembly interface presents a second interfacial energy
• the difference in interfacial energy between the privileged detachment interface and the assembly interface is greater than or equal to 1000 mJ / m 2 ;
• the preferred detachment interface is a bonding interface by molecular adhesion having a first bonding energy
• the assembly interface is a bonding interface by molecular adhesion having a second bonding energy, the first bonding energy being less than the second bonding energy
• the difference in bonding energy between the privileged detachment interface and the assembly interface is at least of the order of 1000 mJ / m 2 .
• the invention also relates to a method of transferring a useful layer from a donor substrate to a recipient substrate, comprising the following steps: a) providing a removable structure as above, b) applying d 'a mechanical stress at the level of a dismantling edge of the removable structure, said dismantling edge being located closest to the assembly interruption zone and the mechanical stress being able to initiate a separation wave at the assembly interface or at the privileged detachment interface, c) if the initiation of the separation wave occurs at the assembly interface, the deviation of the separation wave in the detachment interface privileged when the separation wave passes through the assembly interruption zone, d) the propagation of the separation wave at the privileged detachment interface, to result in the total separation of the dismountable structure.
• step a) comprises: o the supply of the donor substrate comprising the useful layer placed on the initial substrate, the privileged detachment interface being located between said useful layer and said initial substrate, o the supply of a recipient substrate, the formation of at least one cavity opening at the level of a face to be assembled of the recipient substrate or at the level of a face to be assembled of the useful layer, in a peripheral region of the recipient substrate or of the useful layer, o l assembly of the useful layer and of the receiving substrate at the level of their respective faces to be assembled.
• Figures la and lb show respectively a sectional view and a plan view of a removable structure according to the invention; in the plan view, the cavities are made visible for a better understanding of their distribution and location, whereas they should be masked because they are arranged between the useful layer and the receiving substrate.
• FIGS. 2a, 2b and 2c respectively show a sectional view and two views in the plan, of a removable structure according to the invention; on the views in the plan, the cavities are made visible for a better understanding of their distribution and location, whereas they should be masked because they are placed between the useful layer and the receiving substrate.
• FIG. 4a shows a plan view of a structure that can be dismantled during the step of applying a mechanical stress, step of the transfer method according to the invention
• FIG. 4b shows a photo, zoomed around the assembly interruption zone, of the transfer of a useful layer onto a receiving substrate at the end of the transfer process according to the present invention.
• the figures are schematic representations which, for the sake of readability, are not to scale. Specifically, the thicknesses of the layers along the z axis are not to scale with respect to the lateral dimensions along the x and y axes.
• the invention relates to a removable structure 100 comprising at least two interfaces, an assembly interface 30 and a privileged detachment interface 1.
• the two interfaces extend in planes parallel to the plane (x, y). ⁇
• removable structure is understood to mean a structure 100 intended to be subjected to a mechanical stress in order to initiate a separation, desired at the level of the privileged detachment interface 1; due to the presence of the second interface (assembly interface 30), there is competition for propagation of the separation wave between the two interfaces 1.30.
• the removable structure 100 comprises a donor substrate 10 including a useful layer 3 to be transferred placed on an initial substrate 2; the privileged detachment interface 1 is located between the useful layer 3 and the initial substrate 2.
• the useful layer 3 can be formed from a semiconductor material, such as silicon, silicon carbide, germanium, a III-V compound, ..., and / or an insulating material , in particular piezoelectric, such as lithium tantalate or lithium niobate.
• a semiconductor material such as silicon, silicon carbide, germanium, a III-V compound, ..., and / or an insulating material , in particular piezoelectric, such as lithium tantalate or lithium niobate.
• piezoelectric such as lithium tantalate or lithium niobate.
• the useful layer 3 can also comprise a plurality of films of different materials, and / or functional structures (for example cavities) in particular on its face vis-à-vis the receiving substrate 30, and / or all or part of microelectronic components.
• the adhesion between the different films or stacks of components is of course expected higher than the holding of the privileged detachment interface 1, the characteristics of which will be detailed below. In general, the characteristics of the useful layer 3 depend on the targeted application and the desired functionalities.
• the useful layer 3 has a thickness between a few hundred nanometers and a few hundred microns, for example between 200 nm and 200 microns, or preferably between 1 micron and 50 microns.
• the initial substrate 2 is advantageously formed by a low-cost material, providing good mechanical support for the handling of the useful layer 3.
• silicon is generally the material of choice because of its material. compatibility with any microelectronic manufacturing line.
• the initial substrate 2 can be in the form of a wafer with a diameter of 100mm to 450mm and a thickness of between 250 and 850 microns for example.
• the initial substrate 2 can alternatively be in other shapes (square for example).
• the removable structure 100 further comprises a recipient substrate 20, assembled on the donor substrate 10: the assembly interface 30 is located between the recipient substrate 20 and the useful layer 3.
• the receiving substrate 20 may be formed by an insulating material, semiconductor or conductor, solid or comprising a plurality of layers or functional surface structures (for example cavities), or even comprising all or part of active or passive components.
• the characteristics of receiving substrate 20 depend mainly on the intended application and the desired functionalities.
• the receiving substrate 20 can be in the form of a wafer with a diameter of 100mm to 450mm and a thickness of between 250 and 850 microns for example.
• the removable structure 100 according to the invention is intended to be separated, at the level of the privileged detachment interface 1, so as to transfer the useful layer 3 from the donor substrate 10, to the recipient substrate 20.
• the mechanical strength of the privileged detachment interface 1 is therefore lower, or even much lower, than the mechanical strength of the assembly interface 30, as is usually the case in a removable structure comprising two interfaces.
• a difference in mechanical strength or interfacial energy of at least of the order of 1000 mJ / m 2 between the two interfaces 1.30 will be sought.
• the preferred detachment interface 1 is a bonding interface by molecular adhesion having a first bonding energy E1.
• the assembly interface 30 can then be a direct bonding interface, by molecular adhesion, by thermocompression or the like, exhibiting a second bonding energy E2, the first bonding energy E1 being less than the second bonding energy E2.
• the difference between the first E1 and the second E2 bonding energies can be obtained by managing the surface roughness of the faces to be bonded, by the materials brought into contact for bonding by molecular adhesion, by the chemical treatment (wet cleaning or plasma activation) applied to the faces prior to bonding, etc.
• Materials such as silicon oxide, silicon nitride can be deposited on the faces to be bonded (to form the privileged detachment interface 1 or the assembly interface 30) and treated (cleaning, polishing, plasma activation , etching, ...) so as to adjust the interfacial energy resulting from bonding by molecular adhesion of said faces.
• the difference in bonding energy (E2-E1) between the two interfaces 1.30 is chosen, at least of the order of 1000 mJ / m 2 .
• the first bonding energy E1 could be of the order of 2000 mJ / m 2
• the second bonding energy E2 could be greater than 3000 mJ / m 2 .
• a bonding energy can in particular be evaluated by measuring the Mazara blade.
• the removable structure 100 according to the invention is remarkable in that the assembly interface 30 has an assembly interruption zone 31 comprising at least one cavity 31a arranged in the receiving substrate 20 or in the useful layer 3.
• the assembly interruption zone 31 corresponds to a zone where the assembly interface is interrupted, that is to say that there is no contact between the receiving substrate 20 and the useful layer 3.
• the assembly interruption zone 31 is located in a peripheral region of the removable structure 100.
• the assembly interruption zone 31 is located less than 10mm from the edges 100a of said structure 100.
• the zone assembly interruption 31 is even positioned less than 8mm from the edges 100a of the removable structure, or even less than 5mm, or even less than 3mm.
• the removable structures 100 formed from the assembly of two microelectronic grade 10,20 wafers have a peripheral exclusion zone 100b, not glued, linked to the edge geometry of said wafers (chamfer) or to the edge geometry of the useful layer 3 present on one of the two plates; this exclusion zone 100b rarely exceeds 1mm to 2mm.
• the assembly interruption zone 31 is offset radially towards the interior of the removable structure 100 with respect to said exclusion zone 100b, since it must, by definition, interrupt the assembly interface 30 which brings the receiving substrate 20 into contact with the useful layer 3. It could for example be positioned at 0.5mm, 1mm or 2mm from the exclusion zone 100b.
• the assembly interruption zone 31 is very localized, that is to say that it does not extend, in the peripheral region, along the entire perimeter of the removable structure 100, but only over a length from a few hundred microns (200 microns typically) to a few tens of millimeters (50mm to 100mm typically), for example between 1mm and 20mm, preferably between 5mm and 15mm. This has the advantage of limiting its impact on the usable surface of the useful layer 3.
• the assembly interruption zone 31 comprises at least one cavity 31a formed either in the receiving substrate 20 (as illustrated in FIG. La), or in the useful layer 3 (as illustrated in FIG. 2a). It should be noted that in the case where the (at least one) cavity 31a is arranged in the useful layer 3, its depth may for example vary between 5% and 95% of the thickness of the useful layer 3, of course never exceeding in depth the thickness of said layer 3.
• the assembly interruption zone 31 comprises a plurality of cavities 31a.
• the cavities 31a can for example be spaced from each other by a distance of between 1 micron and 1 mm, typically between a few microns and a few hundred microns, for example 500 microns. They can be aligned on a straight line or on a curved line in the (x, y) plane parallel to the assembly interface 30.
• the straight line is preferably parallel to the edge 100a of the removable structure 100 or parallel to the tangent. T at said edge 100a (figures lb and 2c).
• the curved line may have a convex curvature oriented towards the center of the removable structure 100; in other words, as can be seen in the example of FIG. 2b, the curved line follows a curvature opposite to that of the edges 100a of the removable structure 100.
• the cavity 31a has lateral dimensions of between a few microns and a few millimeters, and typically between 20microns and 1mm. It can also have a depth of between 0.5 microns and several tens of microns, typically up to 20 microns, 50 microns, or even up to 100 microns; for example the cavity 31a can have a depth of 3 microns.
• the percentage of the contact zones between the receiver substrate 20 and the useful layer 3 is preferably less than 80%, or even less than 50%.
• the (at least one) cavity 31a of the assembly interruption zone 31 may have, in a plane (x, y) parallel to the assembly interface 30, a square, rectangular, triangular, trapezoidal or rounded periphery. .
• At least one rectilinear segment of the periphery of the cavity 31a is parallel to a dismantling edge 100a 'of the removable structure 100 or to the tangent T to a dismantling edge 100a' of the removable structure 100.
• a rectilinear segment of the periphery of the cavity 31a which has the greatest lateral dimension, is parallel to a dismantling edge 100a 'of the dismantling structure 100 or to the tangent T to a dismantling edge 100a' of the removable structure 100.
• the long side of the cavities 31a in the plane (x, y) would be arranged parallel to the tangent T.
• the shape of the cavity 31a is not symmetrical, there is a preferred direction for orienting the pattern of the cavity 31a with respect to the dismantling edge 100a '(or to its tangent T) or more precisely with respect to the direction of propagation of the separation wave, as will be described with reference to the transfer method according to the invention. It appears more advantageous for a segment of larger dimension to be crossed last by the separation wave. In the example of FIG. 2c, if the cavities 31a of the assembly interruption zone 31 have a triangular periphery, it is therefore advantageous to position them so that the vertex of the triangle points towards the dismantling edge 100a ' .
• the invention also relates to a method of transferring a useful layer 3 from a donor substrate 10 onto a recipient substrate 20.
• the method firstly comprises a step a) of providing a removable structure 100 as described above.
• step a) comprises the sub-steps below, referenced al) to a4).
• a step a1) consists in providing the donor substrate 10 which comprises the useful layer 3 placed on the initial substrate 2, the privileged detachment interface 1 being located between said useful layer 3 and said initial substrate 2 (figure 3a).
• the useful layer 3 of the donor substrate 10 can be produced by any known layer transfer technique, for example:
• the useful layer 3 comes from a useful substrate bonded to the initial substrate and then thinned.
• the useful layer 3 also comes from a useful substrate implanted in light species, bonded to the initial substrate, then separated at the level of the buried fragile plane defined by the implantation.
• the bonding mentioned in these different techniques lead to the development of the preferred detachment interface 1. It is therefore necessary to adjust the bonding parameters (materials in contact, roughness of the surfaces to be bonded, cleaning and chemical activation treatments. surfaces to be bonded, etc.) so as to obtain the first bonding energy (or first interfacial energy) E1 in the desired range, after the donor substrate 10 has potentially undergone heat treatments. This is in particular the case when films are deposited, and / or functional structures are made, and / or all or part of components are produced on or in the useful layer 3, before its transfer to the receiving substrate 20.
• the first bonding energy (or first interfacial energy) E1 is between 1000 mJ / m 2 and 3000 mJ / m 2 .
• an energy difference of at least 1000 mJ / m 2 will advantageously be aimed at between the privileged detachment interface 1 (energy El) and the assembly interface 30, which will be formed in a subsequent step. a4) of the process.
• Step a2) of the method consists in providing the receiving substrate 20, the characteristics of which depend on the intended application and the desired functionalities as mentioned above (FIG. 3b).
• the following step a3) comprises the formation of one or more cavity (s) 31a opening at the level of a face to be assembled 20c of the receiving substrate 20 (FIG. 3c (i)) or at the level of a face to be assembled 3c of the useful layer 3 (FIG. 3c (ii)), in a peripheral region respectively of the receiving substrate 20 or of the useful layer 3.
• This (at least one) cavity 31a will make it possible to form the assembly interruption zone 31 when the donor substrate 10 will be assembled on the recipient substrate 20.
• the assembly interruption zone 31 is located in a peripheral region of the donor substrate 10 or of the recipient substrate 20, less than 10 mm from the edges.
• the assembly interruption zone 31 is even positioned less than 8mm from the edges of said substrates, less than 5mm, or even less than 3mm.
• the assembly interruption zone 31 is preferably very localized, that is to say that it does not extend, in the peripheral region, along the entire periphery of the donor substrate 10 or of the recipient substrate 20, but only over a length of a few hundred microns to a few tens of millimeters.
• each cavity 31a preferably has lateral dimensions of between a few microns and a few millimeters, a depth of between 0.5 microns and several tens of microns and various shapes in the (x, y) plane.
• a step a4) comprises the assembly of the useful layer 3 and of the receiving substrate 20 at the level of their respective faces to be assembled 3c, 20c, to form the removable structure 100 (FIG. 3d (i) and (ii)).
• the assembly of the two substrates can be carried out by direct bonding by molecular adhesion, by metal bonding or by adhesive bonding, depending on the intended application and the compatibility of said bondings.
• Step a4) can comprise, prior to bringing the substrates 10, 20 into contact, sequences of cleaning, deposition of layers favorable to bonding, surface activation or other surface preparations.
• Step a4) can comprise, after bringing the substrates 10,20 into contact, heat treatments consolidation of the assembly interface 30, at more or less high temperature, depending on the type of bonding and the nature of the materials assembled and composing the substrates 10.20.
• the assembly interface 30 formed at the end of this step a4) has a bonding energy E2 greater than the bonding energy E1 of the privileged detachment interface 1.
• the difference between the energy bonding E2 and the bonding energy E1 is of the order of 1000mJ / m 2 , or even greater.
• the method according to the invention comprises a step b) consisting in the application of a mechanical stress at an edge of dismantling 100a 'of the removable structure 100 (FIG. 3e (i) and (ii)).
• the dismantling edge 100a ' is located closest to the assembly interruption zone 31 and the mechanical stress is able to initiate a separation wave in the assembly interface 30 or in the privileged detachment interface 1
• mechanical stress can be applied by inserting a bevel 40 between the edges of the assembled donor 10 and recipient 20 substrates. It can alternatively be applied by injection of a liquid or gaseous fluid between these same edges, or by any other suitable technique.
• the direction of the propagation wave is in the plane (x, y) and perpendicular to the dismantling edge 100a 'or to the tangent T to the dismantling edge 100a'.
• a removable structure 100 it is usual for a removable structure 100 to have a peripheral exclusion zone, due to the edge geometry of the donor 10 and recipient 20 substrates. Note that this exclusion zone is not shown on FIGS. 3a to 3g for the sake of simplicity.
• a mechanical stress for example by inserting a bevel 40 it is possible that the separation wave 41 starts at the assembly interface 30, despite the lower mechanical strength of the interface. of privileged detachment 1. This start of the separation wave 41 in the assembly interface 30 is in particular favored by the presence of the exclusion zone, which gives direct access to said interface 30.
• step c the method according to the invention continues with step c), during which, if the initiation of the separation wave 41 takes place at the assembly interface 30, a deviation of the Separation wave in the privileged detachment interface 1 occurs when the separation wave 41 passes through the assembly interruption zone 31 (Fig. 3f (i) and (ii)).
• the cavities 31a of the assembly interruption zone 31 make it possible to modify the stress field at the head of the front of the separation wave 41, favoring its deviation towards the interface of lower energy, by the occurrence the privileged detachment interface 1.
• the mechanical stress is applied so that the direction of propagation of the separation wave 41, parallel to the y axis in the figures, is perpendicular to at least one rectilinear segment of a periphery of the (or of) cavity (s) 31a of the assembly interruption zone 31 (FIG. 4a).
• the mechanical stress is applied so that the direction of propagation of the separation wave 41 is perpendicular to a rectilinear segment of a periphery of the cavity 31a which has the largest lateral dimension.
• This case may for example be encountered when the cavity (s) 31a has (have) a rectangular shape.
• the the largest dimension of the rectangle (length) will preferably be oriented so as to be perpendicular to the direction of propagation of the separation wave 41.
• the separation wave 41 when the separation wave 41 is initiated directly in the privileged detachment interface 1 in step b), the passage of said wave at the level of the assembly interruption zone 31 does not modify not its location: after crossing the interruption zone 31, the separation wave 41 continues to propagate at the privileged detachment interface 1.
• the transfer method then comprises a step d) of propagation of the separation wave at the level of the privileged detachment interface 1, to result in the total separation of the removable structure 100 (FIGS. 3g (i) and 3g (ii )).
• the separation wave 41 easily propagates along the privileged detachment interface 1, of lower mechanical strength, or spontaneously, the mechanical stress applied to initiate the separation wave 41 being sufficient to propagate the separation wave, either by continuously or intermittently maintaining the application of mechanical stress.
• FIG. 4b shows a photo in top view, of a useful layer 3 (in silicon) transferred onto a receiving substrate 20 (in silicon) from a removable structure 100 according to invention.
• the photo shows in particular a zoom around the assembly interruption zone 31, which is formed in the receiving substrate 20.
• the deviation of the separation wave between the assembly interface 30 is observed (direct bonding of oxide type SiO 2 / silicon) upstream of the assembly interruption zone 31, and the privileged detachment interface (direct bonding of the SiO 2 / Si02 type), downstream of the assembly interruption zone 31.
• the useful layer 3 is transferred onto the receiving substrate 20.
• the eight cavities 31a forming the assembly interruption zone 31 are square in shape, with lateral dimensions of 500 microns. x 500 microns and 3 microns deep. They are located about 3mm from the edge.
• the transfer method applied to the removable structure 100 according to the present invention makes it possible to effectively deflect the separation wave 41, from the assembly interface 30 of the removable structure 100 to the privileged detachment interface. It is thus possible to maximize the surface transferred from the useful layer 3 to a receiving substrate 20 and to transfer a useful layer 3 of high quality.
• the privileged detachment interface 1 could be constituted by a buried fragile plane obtained by implantation of light species, or by formation of a layer of porous material (for example porous silicon), or even by formation of multilayer deposits. one interface of which has low energy (for example as described in application FR3082997).
• the present method applies as soon as the removable structure 100 comprises two interfaces 1.30 exhibiting a sufficient difference in interfacial energy, in particular greater than or equal to 1000 mJ / m 2 .

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• 2020
  • 2020-04-01 FR FR2003263A patent/FR3109016B1/fr active Active
• 2021
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