A peelable temporary substrate capable of handling very high temperatures and a process for transferring a working layer from said substrate - Patents.com

Abstract

The present invention relates to a temporary substrate (10) that can be delaminated at a delamination temperature above 1000°C, the temporary substrate comprising: a semiconductor processing layer extending along a major surface; a carrier substrate; an intermediate layer disposed between the processing layer and the carrier substrate and having a thickness of less than 20 nm along an axis perpendicular to the major surface; a bonding interface located within or adjacent to the intermediate layer; and a maximum concentration of 10 21 / cm 3 and atoms of at least one gaseous species distributed according to a concentration profile along an axis perpendicular to the major plane exceeding 10 nm, wherein the atoms are kept confined in the intermediate layer, in adjacent layers of the carrier substrate having a thickness of 10 nm or less, and / or in adjacent sublayers of the processing layer having a thickness of 10 nm or less when the temporary substrate is exposed to temperatures below the delamination temperature, and wherein the atoms are intended to diffuse to the delamination interface when the temporary substrate is exposed to temperatures above the delamination temperature.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to the field of semiconductor materials for microelectronic components. The invention particularly relates to a temporary substrate which can be peeled off at temperatures above 1000° C., or even above 1200° C., and to a process for producing such a temporary substrate. The invention further relates to a process for transferring a working layer, for example made of monocrystalline silicon carbide, from said temporary substrate to a receiver substrate. Description of the Prior Art

[0002] (Technical Background of the Invention) Interest in silicon carbide (SiC) has increased significantly in recent years due to this semiconductor material's ability to enhance energy processing capabilities. SiC is increasingly being used to manufacture innovative power devices, serving the needs of growing sectors of electronics, particularly electric vehicles.

[0003] Power devices and integrated power systems based on monocrystalline silicon carbide are able to manage much higher power densities than their conventional homologues made of silicon, achieving high power densities with smaller active zone dimensions. To further limit the dimensions of power devices based on SiC, it is advantageous to manufacture vertical components instead of lateral. For this purpose, the SiC structure must allow vertical electrical conduction between electrodes arranged on the front and rear sides of the structure.

[0004] Nevertheless, monocrystalline SiC substrates for the microelectronics industry remain expensive and difficult to supply in large sizes. It is therefore advantageous to use thin layer transfer solutions, which typically produce composite structures with a thin layer of monocrystalline SiC on a cheaper carrier substrate. One well-known thin layer transfer solution is the Smart Cut™ process, which is based on light ion implantation and bonding by direct bonding. Such a process makes it possible to produce composite structures with a thin layer made of monocrystalline SiC (c-SiC), for example, obtained from a donor substrate made of c-SiC and in direct contact with a carrier substrate made of polycrystalline SiC (p-SiC), which allows vertical electrical conduction.

[0005] Further known is the document US Pat. No. 8,436,363, which describes a process for manufacturing a composite structure comprising a thin layer made of c-SiC, arranged on a metal carrier substrate, the thermal expansion coefficient of which matches that of the thin layer. The manufacturing process comprises the steps of forming a buried weakened plane in the c-SiC donor substrate and defining a thin layer between said buried weakened plane and the front surface of the donor substrate. A metal layer, for example of tungsten or molybdenum, is then deposited on the front surface of the donor substrate to form a carrier substrate having a sufficient thickness to act as a stiffener. The process finally comprises the steps of separation along the buried weakened plane to form, on the one hand, a composite structure comprising a metal carrier substrate and a thin layer made of c-SiC, and, on the other hand, the remaining part of the c-SiC donor substrate.

[0006] However, such a manufacturing process is not compatible when the material forming the carrier substrate is p-SiC, which requires deposition at temperatures above 1200° C. (the usual temperature for manufacturing p-SiC). In particular, at such high temperatures, the growth rate of the voids present at the embedded weak surface is faster than that of the p-SiC layer, which does not reach the thickness required for the reinforcement effect before the onset of blistering, which is associated with the deformation of the layer in the vertical direction in response to the voids. Summary of the Invention

[0007] (Subject of the Invention) The present invention relates to an alternative solution to the prior art solutions, aiming at overcoming the above mentioned drawbacks completely or partially. The invention particularly relates to a temporary substrate that can be released at very high temperatures, and to the associated manufacturing process. The invention further relates to a process for transferring a working layer, which may in particular be made of monocrystalline silicon carbide, from the temporary substrate to a receiver substrate in order to form a composite structure.

[0008] BRIEF DESCRIPTION OF THE DRAWINGS The present invention relates to a temporary substrate that can be peeled off at a peeling temperature exceeding 1000° C., the temporary substrate comprising: a semiconductor processing layer extending along a major surface; A carrier substrate; an intermediate layer disposed between the processing layer and the carrier substrate and having a thickness along an axis perpendicular to the major surface of the intermediate layer of less than 20 nm; a bonding interface located within or adjacent to the intermediate layer; Maximum concentration is 10 21 / cm 3 and atoms of at least one gaseous species distributed according to a concentration profile along an axis perpendicular to the main plane exceeding a concentration profile along ...

[0009] According to other advantageous, non-limiting characteristics of the invention, taken alone or in any technically feasible combination, the following apply:

[0010] The working layer includes silicon carbide, diamond, and / or gallium nitride.

[0011] The intermediate layer is formed of at least one material selected from the group consisting of tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, and amorphous silicon.

[0012] The gas species may be nitrogen, helium, argon, xenon, and / or hydrogen.

[0013] The carrier substrate comprises a material whose coefficient of thermal expansion is equal to or close to the coefficient of thermal expansion of the working layer.

[0014] The present invention also relates to a process for producing a temporary substrate as described above, said process comprising the steps of: a) providing a donor substrate; b) implanting light ions selected from hydrogen, helium or a combination of the two into the donor substrate to form a buried weak surface in said donor substrate, said buried weak surface defining, together with the front surface of the donor substrate, a textured layer; c) providing a carrier substrate having a front surface; d) depositing at least one film intended to form an intermediate layer on the front side of the donor substrate and / or on the front side of the carrier substrate; e) bonding the donor substrate and the carrier substrate such that at least one film is disposed between said substrates forming an intermediate layer; f) Separating along the buried weakened surface to form, on the one hand, the temporary substrate and, on the other hand, the remaining part of the donor substrate.

[0015] The manufacturing process is Prior to the depositing step d), a deposition step is performed on the donor substrate and / or the carrier substrate from the respective front surface to a depth of 10 nm or less, After the depositing step d), to at least one film, or After the separating step f), into the intermediate layer, The method further comprises the step of introducing atoms of at least one gaseous species into:

[0016] According to other advantageous, non-limiting characteristics of the invention, taken alone or in any technically feasible combination, the following apply:

[0017] The step a) of providing a donor substrate comprises epitaxially growing a donor layer on an initial substrate to form the donor substrate.

[0018] The initial substrate and the donor layer are made of silicon carbide, and step a) includes forming a single crystal conversion layer on the initial substrate and converting basal plane dislocation defects in the initial substrate into threading edge dislocation defects prior to epitaxial growth of the donor layer.

[0019] The epitaxial growth is carried out at a temperature above 1200°C, preferably between 1500°C and 1650°C.

[0020] Step f) involves a heat treatment at a temperature between 900°C and 1200°C.

[0021] The invention finally relates to a process for transferring the working layer from the temporary substrate to a receiver substrate, said process comprising the steps of: g) forming a peelable structure comprising a receiver substrate disposed on a working layer of a temporary substrate, the forming step including treatment at a first temperature of 1000° C. or higher; h) peeling the peelable structure along a peel interface within or adjacent to the intermediate layer, the step including a heat treatment at a peel temperature higher than the first temperature to form a composite structure comprising a processed layer arranged on a receiver substrate on the one hand and a carrier substrate on the other hand.

[0022] According to other advantageous, non-limiting characteristics of the invention, taken alone or in any technically feasible combination, the following apply:

[0023] Step g) comprises depositing a receiver substrate onto the free surface of the working layer of the temporary substrate.

[0024] Deposition of the receiver substrate is carried out by thermal or enhanced chemical vapour deposition, or by evaporation, at a temperature above 1000° C., preferably above 1200° C.

[0025] The receiver substrate formed is made of polycrystalline silicon carbide.

[0026] The receiver substrate is a bulk substrate, and step g) comprises bonding the receiver substrate to the free surface of the working layer of the temporary substrate.

[0027] The joining step includes direct bonding by molecular adhesion and heat treatment at temperatures of 1000° C. or higher, or even 1200° C. or higher.

[0028] Step h) comprises a heat treatment at a temperature of 1400° C. or higher, or even 1500° C. or higher.

[0029] The transfer process includes a step i) of finishing the composite structure, which includes a process of chemical cleaning, chemical etching and / or chemical mechanical polishing of the front side of the composite structure, which is the free side of the working layer.

[0030] Step i) comprises a process of chemical cleaning, chemical etching, mechanical grinding and / or chemical-mechanical polishing of the rear face of the composite structure, which is the free face of the receiver substrate.

[0031] The transfer process includes a step g') of treating the releasable structure prior to the releasable step h), including steps of chemical cleaning, chemical etching, mechanical grinding, and / or chemical-mechanical polishing of the rear surface of the receiver substrate.

[0032] The transfer process includes a step j) of reconditioning the carrier substrate for reuse as a carrier substrate for a new temporary substrate.

[0033] The transfer process may include the fabrication of electronic components in or on the working layer of the composite structure, possibly followed by epitaxial growth of additional layers on the working layer.

[0034] Other features and advantages of the present invention will become apparent from the following detailed description of the invention, which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0035] [Figure 1a] FIG. 2 shows a peelable temporary substrate according to the present invention. [Figure 1b] FIG. 2 is an enlarged view of an intermediate layer of a peelable temporary substrate according to the present invention. [Figure 2a] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 2b] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 2c] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 2d] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 2e] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 2f] 1A-1D illustrate a process for manufacturing a peelable temporary substrate according to the present invention. [Figure 3a] FIG. 2 shows a particular embodiment of step a) of the manufacturing process according to the invention. [Figure 3b] FIG. 2 shows a particular embodiment of step a) of the manufacturing process according to the invention. [Figure 4-1] 3A-3D show steps of a process for manufacturing a releasable temporary substrate according to a first embodiment. [Figure 4d] 3A-3D show steps of a process for manufacturing a releasable temporary substrate according to a first embodiment. [Figure 4e] 3A-3D show steps of a process for manufacturing a releasable temporary substrate according to a first embodiment. [Figure 4f] 3A-3D show steps of a process for manufacturing a releasable temporary substrate according to a first embodiment. [Figure 5-1] 5A-5D show process steps for manufacturing a peelable temporary substrate according to a second embodiment of the present invention. [Figure 6-1] 5A-5D show process steps for manufacturing a peelable temporary substrate according to a third embodiment of the present invention. [Figure 7g] FIG. 2 illustrates steps of a migration process according to the present invention. [Figure 7h] FIG. 2 illustrates steps of a migration process according to the present invention. [Figure 7i] FIG. 2 illustrates the steps of a migration process according to the present invention. [Figure 7j] FIG. 2 illustrates the steps of a migration process according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Detailed Description of the Invention In the description, the same reference numbers in the figures may be used for the same types of elements. The figures are schematic and, for ease of reading, are not drawn to scale. In particular, the thickness of a layer along axis z is not drawn to scale relative to the lateral dimensions along axes x and y. Also, the relative thicknesses of layers with respect to one another are not necessarily taken into account in the figures.

[0037] The present invention relates to a temporary substrate 10 which is peelable at a peeling temperature above 1000° C., preferably even above 1200° C., above 1300° C., above 1400° C. or above 1500° C. Peelable means that the temporary substrate 10 can be separated into two parts at a very high temperature, in this case the working layer 1, which are both parts of the temporary substrate 10, can be transferred to a final receiver substrate by peeling said working layer 1 from the carrier substrate 3.

[0038] The temporary substrate 10 is preferably provided in the form of a wafer having a diameter of 100 mm, 150 mm, 200 mm, or even possibly 450 mm, and a thickness typically between 300 and 800 μm. The temporary substrate 10 has a front surface 10a and a rear surface 3b extending along a major surface (x, y), as shown in Figures 1a and 1b.

[0039] The temporary substrate 10 comprises a semiconductor processing layer 1 arranged on an intermediate layer 2, which is itself arranged on a carrier substrate 3. The temporary substrate 10 also has a bonding interface 4 located within or adjacent to the intermediate layer 2, i.e., between the intermediate layer 2 and the processing layer 1 or between the intermediate layer 2 and the carrier substrate 3.

[0040] The working layer 1, made of a semiconductor material, is the layer in or on which components are intended to be manufactured to address a given application. Since the temporary substrate 10 is particularly suited for semiconductor materials requiring very high processing temperatures, the working layer 1 advantageously comprises silicon carbide. The working layer 1 can of course also comprise one or more materials chosen from among diamond, binary or ternary III-V compounds requiring high manufacturing temperatures, such as gallium nitride or aluminium nitride, or II-VI compounds requiring similarly high processing or manufacturing temperatures (usually above 1000° C. or 1200° C.).

[0041] The processing layer 1 is arranged on an intermediate layer 2, itself provided on a temporary substrate 10. The latter has a thickness, along an axis z perpendicular to the main plane (x, y), that is less than 20 nm, or even less than 10 nm. This small thickness is important in that it allows the temporary substrate 10 to retain good mechanical strength and good compatibility with very high temperatures, even if one or more of the constituent materials of the intermediate layer 2 have a creep or melting temperature lower than the delamination temperature.

[0042] It should be noted that the intermediate layer 2 may extend continuously parallel to the main faces (x,y) or discontinuously, for example in the form of nodules arranged side by side in a plane parallel to the main faces (x,y).

[0043] The intermediate layer 2 may be formed of at least one metal or semiconductor material, for example selected from tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, and amorphous silicon.

[0044] The material of the intermediate layer 2 is selected so that it does not diffuse and / or react, or only very little, with the working layer 1 at the very high temperatures applied during the transfer process that realizes the temporary substrate 10, i.e. over the very thin thickness (less than 10 nm) of the working layer 1. This allows the integrity and purity of the working layer 1 to be maintained.

[0045] The intermediate layer 2 is arranged on a carrier substrate 3, which likewise forms part of the temporary substrate 10. The carrier substrate 3 may be made of any material that is compatible with the high temperatures required or targeted for the processing of the working layer 1. The carrier substrate 3 preferably comprises a material whose thermal expansion coefficient is equal to or close to that of the working layer 1. This material can for example be selected to be of the same nature as the working layer 1, while exhibiting a lower crystalline quality.

[0046] For example, in the particular case where the working layer 1 is made of silicon carbide, the carrier substrate 3 itself may be formed of monocrystalline silicon carbide of lower crystal quality than the working layer 1, or of polycrystalline silicon carbide.

[0047] The temporary substrate 10 has a minimum density of 10 along the axis z. 21 / cm 3 The gas further comprises atoms 2a of at least one gaseous species distributed according to a concentration profile 2b higher than

[0048] As will be explained in more detail in the process of manufacturing the temporary substrate 10, the atoms 2a may be introduced into the substrate and the layers contained therein at different locations and at different times in the process.

[0049] Thus, the concentration profile 2b of the atoms 2a may take various forms, an example in which most of the atoms 2a are located in the intermediate layer 2 is shown in Fig. 1b. Alternatively, most of the atoms 2a may be located in a layer of the carrier substrate 3 adjacent to the intermediate layer 2, the thickness of which is 10 nm or less. In other words, in this case most of the atoms 2a are located in the carrier substrate 3, but very close to the intermediate layer 2. As yet another alternative, most of the atoms 2a may be located in a sublayer of the processing layer 1 adjacent to the intermediate layer 2, the thickness of which is 10 nm or less.

[0050] Wherever atom 2a is located, concentration profile 2b has the highest concentration of atom 2a, at 10 21 / cm 3 More than or even tens of 21 / cm 3 , usually 2 E 21 / cm 3 ~5 E 21 / cm 3 It is necessary to include the region in which the value of

[0051] According to the invention, the atoms 2a are kept confined in the intermediate layer 2, in adjacent layers of the carrier substrate 3 having a thickness of 10 nm or less, and / or in adjacent sublayers of the processing layer 1 having a thickness of 10 nm or less, when the temporary substrate 10 is exposed to a temperature below the delamination temperature, and are intended to diffuse to a delamination interface within or adjacent to the intermediate layer 2, coincident with or adjacent to the bonding interface 4, when the temporary substrate 10 is exposed to a temperature above the delamination temperature.

[0052] The materials and gas species of the intermediate layer 2 are selected to be: Most of the atoms are kept trapped in the intermediate layer 2 due to the high solubility of said gaseous species in the intermediate layer 2 when the temporary substrate 10 is exposed to a temperature below the release temperature, or Most of the atoms are kept confined in adjacent thin layers of the carrier substrate 3 and / or adjacent thin sublayers of the processing layer 1, since the intermediate layer 2 forms an effective barrier against said species when the temporary substrate 10 is exposed to temperatures below the delamination temperature.

[0053] Most of the trapped atoms 2a therefore accumulate at the delamination interface once a critical temperature (the delamination temperature) is exceeded, causing delamination along said interface, as further explained in the transfer process using the temporary substrate 10.

[0054] The gas species is preferably selected from among nitrogen, helium, argon, xenon, and / or hydrogen.

[0055] The process of manufacturing the temporary substrate 10 will now be described with reference to Figures 2a to 2g, 3a and 3b.

[0056] The manufacturing process first comprises a step a) of providing a donor substrate 11 having a front surface 11a and a rear surface 11b (FIG. 2a). The donor substrate 11 is the origin of the working layer 1 of the temporary substrate 10 and therefore comprises at least the material that will form the working layer 1.

[0057] The surface roughness of the front surface 11a of the donor substrate 11 is advantageously chosen to be less than 1 nmRa (average roughness), measured by means of an atomic force microscopy (AFM) scan of 20 μm×20 μm.

[0058] According to a first option, the donor substrate 11 is a bulk substrate with the desired level of quality for the processing layer 1 , which comes directly from the donor substrate 11 .

[0059] According to a second option, step a) comprises epitaxially growing a donor layer 110 on an initial substrate 111 to form the donor substrate 11. The donor layer 110 preferably has a lower crystalline defect density than the crystalline defect density of the initial substrate 111 (FIG. 3a).

[0060] Step a) may, in the particular case in which the initial substrate 111 and the donor layer 110 are made of silicon carbide, comprise forming a monocrystalline conversion layer 112 in the initial substrate 111 and converting basal plane dislocation defects of the initial substrate 111 into threading edge dislocation defects prior to the epitaxial growth of the donor layer 110 ( FIG. 3 b). 2 The following BPD defect densities are targeted:

[0061] The epitaxial growth of silicon carbide is carried out at temperatures above 1200° C., preferably between 1500° C. and 1650° C. The precursors used are monosilane (SiH4), propane (C3H8) or ethylene (C2H4), and the carrier gas may be hydrogen with or without argon.

[0062] It should be noted that prior to the epitaxial growth of the donor layer 110 (and / or the conversion layer 112), a conventional sequence may be carried out to clean and / or etch the initial substrate 111 in order to remove all or part of any particulates, metallic or organic contaminants, or any native oxide layer that may be present on the front surface of the initial substrate 111.

[0063] The manufacturing process then comprises a step b) of implanting the donor substrate 11 (and especially the donor layer 110, if present) with light ions selected from among hydrogen, helium or a combination of both species, in order to form a buried weak surface 5 of said donor substrate 11 (FIG. 2b). The buried weak surface 5 together with the front surface 11a of the donor substrate 11 defines the textured layer 1.

[0064] As is well known for the Smart-Cut™ process, these light species will form tiny voids around the implantation depth distributed in a thin layer parallel to the front surface 11a of the donor substrate 11, i.e. parallel to the plane of the drawing (x,y). This thin layer will be called the buried weak plane 5 for simplicity.

[0065] The implantation energy of the light species is selected to reach a determined depth in the donor substrate 11, which corresponds to the target thickness of the processing layer 1. For example, hydrogen ions can be implanted at 500 nm with energies between 10 keV and 250 keV. E 16 / cm 2 ~1 E 17 / cm 2 When this dose is implanted, a processed layer 1 having a thickness of about 100 to 1500 nm is defined.

[0066] It should be noted that, prior to the step of ion implantation of light species, a protective layer may be deposited on the front side 11a of the donor substrate 11. This protective layer may for example consist of a material such as silicon oxide or silicon nitride.

[0067] The process for manufacturing the temporary substrate 10 then comprises step c), which is to provide a carrier substrate 3 (FIG. 2c).

[0068] The carrier substrate 3, as mentioned above, provides mechanical support to the temporary substrate 10 and is not intended to be retained in the final composite structure 51 designed for a given application. Therefore, the main properties of the carrier substrate 3 are preferably low cost and reliability as a mechanical support for the working layer 1.

[0069] The manufacturing process then comprises a step d) of depositing at least one film 21, 22 on the donor substrate 11 and / or on the carrier substrate 3 (Fig. 2d). In other words, a first film 21 may be deposited on the front surface 11a of the donor substrate 11 and alternatively or additionally a second film 22 may be deposited on the front surface 3a of the carrier substrate 3. In the example shown in Fig. 2d, the first film 21 and the second film 22 are deposited on the donor substrate 11 and the carrier substrate 3, respectively.

[0070] It should be noted that at least one of the deposited films 21 , 22 is intended to form an intermediate layer 2 of the temporary substrate 10 .

[0071] At least one of the deposited films 21, 22 has a thickness along an axis z perpendicular to the main plane (x, y) of less than 20 nm, or even less than 10 nm, for example between 0.3 nm and 10 nm.

[0072] At least one membrane 21, 22 may be formed of at least one material selected from among, for example, tungsten, nickel, titanium, aluminum, molybdenum, tantalum, titanium nitride, tantalum nitride, amorphous silicon.

[0073] The deposition of step d) may be carried out using any known technique, such as direct liquid injection, plasma-enhanced, thermal, chemical vapour deposition (CVD), sputtering or evaporation deposition, among others.

[0074] The manufacturing process then comprises a step e) of bonding the donor substrate 11 and the carrier substrate 3, whereby at least one membrane 21, 22 is arranged between said substrates 11, 3, forming an intermediate layer 2 (figure 2e).

[0075] The donor substrate 11 and the carrier substrate 3 are bonded at their respective front faces 11a, 3a to form a laminate 311. The two substrates may be bonded using direct bonding, as is well known per se, by molecular adhesion, i.e. in this case by placing the front faces of the substrates 11, 3 in direct contact with one or both of their faces provided with the membranes 21, 22. Bonding can be carried out at ambient temperature or at a temperature below 800° C., in air or in a controlled atmosphere, e.g. under vacuum.

[0076] Step e) may involve, prior to this contact, a conventional sequence of cleaning, surface activation or other surface treatments capable of improving the quality of the bonding interface 4 (low defect density, good adhesion quality).

[0077] The joining or bonding interface 4 is located within the intermediate layer 2 , between the intermediate layer 2 and the processing layer 1 , or else between the intermediate layer 2 and the carrier substrate 3 .

[0078] The manufacturing process then comprises a step f) which involves separation along the buried weak plane 5 to form, on the one hand, the temporary substrate 10 and, on the other hand, the remaining part 11' of the donor substrate (FIG. 2f). The front surface 10a of the temporary substrate 10 is also the front surface of the working layer 1 arising from the donor substrate 11.

[0079] According to one advantageous embodiment, the separation step f) is performed by subjecting the stack 311 to a heat treatment at a separation temperature. Microvoids present in the buried weak surface 5 follow a growth rate until a splitting wave is initiated, which propagates over the entire extent of the buried weak surface 5, resulting in the separation of the temporary substrate 10 from the remaining part 11' of the donor substrate. In practice, for a donor substrate 11 made of silicon carbide, the temperature may be between 900° C. and 1200° C., depending on the implantation conditions of step b).

[0080] According to an alternative embodiment, the separation step f) is performed by applying a mechanical stress to the stack 311 after the heat treatment at a temperature between 900° C. and 1200° C. has been completed in whole or in part. The stress can be applied, for example, by inserting a tool (for example a razor blade) in the vicinity of the embedded weak surface 5. The separation stress may, by way of example, be of the order of a few GPa, preferably greater than 2 GPa.

[0081] As known per se, at the end of the separation step f), the front surface 10a of the processing layer 1 of the temporary substrate 10 has a surface roughness of 5-100 nm RMS (measured by a 20 μm×20 μm scan with an atomic force microscope (AFM)).

[0082] Step f) may optionally include a treatment to smooth and repair the working layer 1 after separation. In particular, mention may be made of a heat treatment in a controlled (oxidizing or reducing) atmosphere, a wet or dry chemical etching to remove damaged surface parts of the working layer 1, and / or a chemical mechanical polishing of the front side of the working layer 1 to restore a good level of roughness (for example a final roughness of less than 0.5 nm RMS, or even less than 0.3 nm in an AFM range of 20x20 μm) and possibly remove damaged surface parts. Conventional cleaning sequences, for example cleaning of SC1 / SC2 type (standard cleaning 1, standard cleaning 2), HF (hydrofluoric acid) and / or plasma with N2, Ar, CF4, etc., may also be applied to the temporary substrate 10 to further improve the quality of the front side 10a of the working layer 1.

[0083] The carrier substrate 3 is selected to be compatible with the working layer 1 and to be mechanically and high temperature stable, and the intermediate layer 2 is selected to be of very small thickness, so that the thermal, mechanical or chemical treatments necessary to restore high quality to the working layer 1 can be easily applied to the temporary substrate 10 without the risk of undesirable stress or damage to the working layer 1.

[0084] It should be noted that step f) can be followed by a step of epitaxial growth of an additional layer on the working layer 1 of the temporary substrate 10. Such a step is applied if a relatively significant thickness is required for the working layer, typically on the order of a few microns to a few tens of microns, for example 5 μm to 50 μm. The epitaxy temperature is advantageously chosen to be lower than 1500° C., or even lower than 1300° C., in order to avoid premature initiation of detachment of the temporary substrate 10.

[0085] The intermediate layer 2 may undergo physical and / or morphological changes during or at the end of step f), which preferably includes a high-temperature heat treatment. At least one film 21, 22 may form intercalated nodules in the continuous area between the material of the working layer 1 and the material of the carrier substrate 3, the intermediate layer 2 being in this case formed of a discontinuous layer of nodules. The bonding interface 4 itself may therefore also change substantially and be located within the nodules, between the nodules and the working layer 1, between the nodules and the carrier substrate 3 and / or between the working layer 1 and the carrier substrate 3. Alternatively, the intermediate layer 2 may retain its continuous morphology all along the bonding interface 4.

[0086] The manufacturing process further comprises the step of introducing atoms 2a of at least one gaseous species into or in the vicinity of at least one of the films 21, 22. The gaseous species may be nitrogen, helium, argon, xenon and / or hydrogen, as mentioned above in the description of the temporary substrate 10. The atoms 2a of this gaseous species are intended to be confined in the intermediate layer 2, in adjacent layers of the carrier substrate 3 having a thickness of 10 nm or less, and / or in adjacent sublayers of the processing layer 1 having a thickness of 10 nm or less.

[0087] In the first embodiment shown in figures 4-1, 4d, 4e and 4f, this step of introducing atoms 2a is carried out before step d) of depositing the films 21, 22, and will therefore be called -1). The atoms 2a are introduced into the donor substrate 11 and / or the carrier substrate 3 from the respective front faces 11a, 3a to a shallow depth of less than 10 nm. Ion implantation can be carried out to introduce the atoms 2a in the form of ions into the substrate or substrates 11, 3, the ion implantation energy being typically less than 10 keV, or even less than 5 keV, the implantation dose being typically less than 200 nm. E 15 / cm 2 ~Number 1 E 16 / cm 2 Thus, an implantation zone 20 is formed near the surface of the front surface 11a of the donor substrate 11 and / or near the surface of the front surface 3a of the carrier substrate 3.

[0088] Process steps d) to f) are in this case carried out as explained above and are illustrated in figures 4d, 4e and 4f.

[0089] The atoms 2a are located in a thin layer (thickness less than 10 nm) of the carrier substrate 3 adjacent to the intermediate layer 2 and in a thin sublayer (thickness less than 10 nm) of the processing layer 1 adjacent to the intermediate layer 2, said adjacent layers and sublayers starting from the implantation zone 20. Depending on the gas species and the nature of the intermediate layer 2, the atoms 2a may remain confined in said layers and sublayers or may become confined in the intermediate layer 2 during the thermal treatment of the temporary substrate 10, as long as the latter is not exposed to temperatures equal to or greater than the delamination temperature, which is significantly higher than the separation temperature of step f).

[0090] The atoms 2a of the gaseous species are distributed according to a concentration profile along an axis z perpendicular to the principal plane (x, y), with a maximum concentration of 10 21 / cm 3 Higher than.

[0091] In the second embodiment shown in FIG. 5-1, the step of introducing atoms 2a is carried out after step d) of depositing the films 21, 22, and will therefore be called -1).

[0092] At least one film 21, 22 may be present on the donor substrate 11 and / or on the carrier substrate 3, as mentioned above.

[0093] The atoms 2a are introduced into at least one of the films 21, 22. Ion implantation can be carried out to introduce the atoms 2a in the form of ions, the ion implantation energy being typically less than 10 keV, or even less than 5 keV, depending on the thickness of the film 21, 22 deposited in step d). The implantation dose is typically less than 2 E 15 / cm 2 ~Number 1 E 16 / cm 2 It is.

[0094] The atoms 2a of the gaseous species are distributed in the intermediate layer 2 according to a concentration profile along the axis z, the maximum concentration being located at the injection peak and being 10 21 / cm 3 Higher than.

[0095] Process steps e) to f) are then carried out as described above (FIG. 2e, FIG. 2f).

[0096] In the third embodiment shown in FIG. 6-1, the step of introducing atom 2a is carried out after the separation step f), and will therefore be referred to as -1).

[0097] The atoms 2a are introduced into the intermediate layer 2, for example by ion implantation. The ion implantation energy depends in this case on the nature and thickness of the working layer 1 through which the ions pass to reach the intermediate layer 2. The implantation dose is typically 2 E 15 / cm 2 ~Number 1 E 16 / cm 2 It is.

[0098] The atoms 2a of the gaseous species are again distributed according to a concentration profile along the axis z, with the maximum concentration located at the injection peak and 10 21 / cm 3 is predicted to be higher.

[0099] In all three described embodiments, the total dose of ions implanted is such that in the completed temporary substrate 10, the concentration profile of atoms 2a is 10 21 / cm 3 It is determined to have a maximum concentration higher than

[0100] By introducing a large dose of atoms 2a of a gaseous species into and / or very close to the intermediate layer 2, it is possible to create a peel interface within or adjacent to the intermediate layer 2 during the transfer process of the present invention described below.

[0101] The present invention also relates to a process for transferring the working layer 1 from the above described temporary substrate 10 to a receiver substrate 50. The transfer process is explained with reference to Figures 7g to 7j.

[0102] The receiver substrate 50 is preferably provided in the form of a wafer having a diameter of 100 mm, 150 mm, 200 mm, or possibly even 450 mm, and a thickness typically between 300 and 800 μm. The receiver substrate 50 has opposed front and rear surfaces 50b. The receiver substrate 50 is designed for the end application, and therefore the physical and electrical properties of the receiver substrate 50 are specifically selected to meet the required specifications.

[0103] In power electronics applications, where the processing layer 1 is made, for example, of silicon carbide of high crystalline quality, the receiver substrate 50 is made, in particular, of polycrystalline silicon carbide and has vertical conductive paths, which allows it to exhibit good electrical conductivity.

[0104] The transfer process includes step g) of forming a peelable structure 510 comprising a receiver substrate 50 disposed on the working layer 1 of the temporary substrate 10 (Fig. 7g). It should be noted that the temporary substrate 10 in Fig. 7g is shown with atoms 2a of the gaseous species trapped in the intermediate layer 2. Any of the other configurations described above, in which the atoms 2a are located elsewhere, can of course be implemented.

[0105] Step g) comprises a treatment at a first temperature which is greater than or equal to 1000°C and advantageously less than or equal to 1500°C.

[0106] According to a first embodiment, step g) comprises the deposition of a receiver substrate 50 on the free face 10a of the working layer 1 of the temporary substrate 10. The deposition may be carried out at temperatures higher than 1000° C., higher than 1200° C. or even higher than 1400° C. (corresponding to the first temperature), in particular if it is desired to deposit a receiver substrate 50 made of high-quality polycrystalline silicon carbide on a working layer 1 made of very high-quality monocrystalline silicon carbide. Of course, other materials deposited at very high temperatures to form the receiver substrate 50 may be interesting.

[0107] In applications requiring electrical conductivity between the working layer 1 and the receiver substrate 50, a non-insulating interface must be defined between them. In other words, step g) is performed such that the interface between the working layer 1 and the receiver substrate 50 is electrically conductive. The resistivity of the interface is typically less than 1 mΩ·cm 2 is the target. Advantageously, removal of the native oxide present on the free surface 10a of the working layer 1 is carried out by HF (hydrofluoric acid) deoxidation in a wet or dry route in order to ensure electrical conductivity at the interface. Alternatively, the electrical conductivity at the interface between the working layer 1 and said substrate 50 may be increased by overdoping the first few nanometers of the deposited receiver substrate 50.

[0108] It may also be advantageous to subject the temporary substrate 10 to a cleaning sequence prior to deoxidation and / or formation of the receiver substrate 50 to remove all or part of any particulate, metallic or organic contaminants that may be present on the free surfaces 10a, 3b of the temporary substrate 10.

[0109] It should be noted that in the first embodiment, the working layer 1 of the temporary substrate 10 does not necessarily have to be polished after the separation in step f) in order to fully restore the surface roughness of the temporary substrate 10. The production of the receiver substrate 50 by deposition or epitaxy at very high temperatures (typically 1100° C.-1500° C.) can facilitate the repair and reconstruction of the surface of the working layer 1 and can even tolerate residual roughness.

[0110] The carrier substrate 3 is selected to be compatible with the processing layer 1 and to be mechanically and high temperature stable, and the intermediate layer 2 is selected to be of very thin thickness so that the thermal, mechanical or chemical treatments required to form the peelable structure 510 can be easily applied to the temporary substrate 10 without the risk of undesirable stress or damage to the processing layer 1.

[0111] In this first embodiment, the deposition of step g) may be carried out using evaporation or chemical vapor deposition (CVD) techniques. Thermal CVD techniques such as atmospheric-pressure CVD (APCVD) or low-pressure CVD (LPCVD), plasma-enhanced CVD (PECVD) or else direct-liquid-injection CVD (DLI-CVD) may be used.

[0112] Returning to the example of a receiver substrate 50 made of silicon carbide, in order to obtain the necessary conductive properties for the power application mentioned above, the substrate may for example exhibit the following structural characteristics: polycrystalline structure, 3C SiC type grains, 111 orientation, average size between 1 and 50 μm, n-type doping with a final resistivity of less than or equal to 0.03 ohm·cm.

[0113] The receiver substrate 50 has, at the end of step g), a thickness typically of 50 μm or more, or even of 100 μm or more, for example of the order of 300 μm. The detachable structure 510 resulting from step g) comprises the receiver substrate 50 arranged on a processing layer 1, itself comprised in a temporary substrate 10. The first temperature realized to produce the receiver substrate 50 is lower than the detachment temperature, so that most of the atoms 2a of the gas species are kept confined in the intermediate layer 2, in adjacent layers of the carrier substrate 3 having a thickness of 10 nm or less, and / or in adjacent sublayers of the processing layer 1 having a thickness of 10 nm or less.

[0114] According to a second embodiment, in which the receiver substrate 50 is a bulk substrate, step g) comprises bonding said receiver substrate 50 to the free surface 10a of the processing layer 1 of the temporary substrate 10 to form a peelable structure 510.

[0115] The bonding process may be carried out using any known technique, in particular using direct bonding by molecular adhesion, thermocompression bonding or another type of bonding compatible with very high temperatures. Step g) further comprises a heat treatment at a temperature of 1000° C. or higher, or even 1200° C. or higher (corresponding to the first temperature) to consolidate this bond.

[0116] The transfer process according to the invention then comprises a step h) of delaminating the delaminating structure 510 along a delamination interface located in or adjacent to the intermediate layer 2. This step forms, on the one hand, a composite structure 51 comprising the working layer 1 arranged on the receiver substrate 50 and, on the other hand, a carrier substrate 3 (FIG. 7h). The delamination step comprises a heat treatment at a delamination temperature higher than the separation temperature of step f) and higher than the first temperature applied in step g). The delamination temperature is higher than 1000° C.

[0117] In the particular case where the intermediate layer 2 comprises tungsten implanted with nitrogen atoms 2a and the processing layer 1 and the carrier substrate 3 are made of SiC, the delamination temperature can typically be 1400°C or higher, or even 1500°C or higher, for example 1600°C or 1700°C.

[0118] The atoms 2a present in the temporary substrate 10 migrate during the course of the thermal treatment of step h) and accumulate at the peel interface coincident with or near the bond interface 4 in or adjacent to the intermediate layer 2. The gas species then generate pressurized microcracks which grow under pressure and cause peeling within the peelable structure 510 over the entire area parallel to the main surface (x, y) of the peelable structure 510.

[0119] According to one particular embodiment, the intermediate layer 2 undergoes segmentation during step h) or during a prior preceding heat treatment into the form of nodules, which are then intercalated in the continuous areas between the material of the working layer 1 and the material of the carrier substrate 3. The accumulation of gaseous species which occurs in step h) then occurs preferentially in said continuous areas and causes pressurized microcracks.

[0120] The delamination phenomenon in the transfer process according to the invention is particularly advantageous since it only occurs at delamination temperatures higher than the very high temperatures previously applied to the temporary substrate 10 or to the releasable structure 510, thus allowing the use of several types of steps for forming said releasable structure 510. The high first temperature makes it possible in particular to achieve a very high quality receiver substrate 50 (in the first embodiment) and / or a very high quality bond of the receiver substrate 50 to the working layer 1 (in the second embodiment) without causing a premature development of the delamination interface at the intermediate layer 2.

[0121] Thus, in a second stage, at a higher delamination temperature, delamination of the delaminationable structure 510 can be caused to form the composite structure 51.

[0122] The transfer process according to the invention may then comprise a step i) of finishing the composite structure 51, comprising a process of chemical cleaning, chemical etching and / or chemical-mechanical polishing of the front surface 51a of the composite structure 51, which is the free surface of the working layer 1. It is noted that chemical etching or polishing may be useful to remove residues of the intermediate layer 2' from the front surface 51a of the composite structure 51.

[0123] Step i) may also comprise a chemical cleaning, chemical etching, mechanical grinding and / or chemical-mechanical polishing process applied to the rear face 50b of the composite structure 51, which is the free face 50b of the receiver substrate 50.

[0124] Polishing or grinding of the edges of the composite structure 51 may also be carried out during this step i) in order to make the annular contour of the edges and the shape of the edge debris compatible with the requirements of the microelectronic manufacturing process, particularly in the first embodiment in which the receiver substrate 50 is formed by deposition.

[0125] Step i) may finally comprise the epitaxial growth of an additional layer of the working layer 1 of the composite structure 51. Such a step is applied when the thickness of the working layer 1 transferred from the temporary substrate 10 is not sufficient for the production of a component, or when a layer with a particular doping type or a particular composition is required at the working surface 1 of said component.

[0126] The transfer process may optionally include a step g') of treating the releasable structure 510 before the peeling step h), including chemical cleaning, chemical etching, mechanical grinding and / or chemical-mechanical polishing of the rear face 50b of the receiver substrate 50 and possibly grinding of the edges of the releasable structure 510. This allows to treat and refine the shape and thickness of the receiver substrate 50 without the risk of damaging the working layer 1 still embedded in the releasable structure 510.

[0127] The transfer process according to the invention may finally comprise a step j) of reconditioning the carrier substrate 3, in particular for reuse as a carrier substrate for a new temporary substrate 10 (FIG. 7j). Such a reconditioning step is based on one or more treatments of the front side of the substrate 3, at the end of step h), by chemical-mechanical polishing, mechanical grinding and / or wet or dry chemical etching of the surface or edges.

[0128] EXEMPLARY EMBODIMENTS According to one non-limiting exemplary embodiment, the initial substrate 111 provided in step a) of the manufacturing process is a wafer made of c-SiC of 4H type crystalline polymorphism, oriented at 4.0°±0.5° relative to the axis <11-20>, with a diameter of 150 mm and a thickness of 350 μm. A conventional cleaning sequence of RCA type (standard cleaning 1+standard cleaning 2), then Caro's acid (mixture of sulfuric acid and hydrogen peroxide), then HF (hydrofluoric acid) is performed on the initial substrate 111 before the epitaxial growth of the donor layer 110 made of c-SiC.

[0129] The growth is carried out in an epitaxy chamber at a temperature of 1650° C. using precursors such as monosilane (SiH4) and propane (C3H8) or ethylene (C2H4) to produce a 30 μm thick c-SiC donor layer 110 (growth rate is 10 μm / hr). 2 The BPD defect density is about

[0130] The hydrogen ions implanted in step b) have an energy of 150 keV and E 16H + / cm 2 is implanted through the free surface of the donor layer 110. In this way, a buried weak surface 5 is created at a depth of about 800 nm in the donor layer 110.

[0131] In step c) a carrier substrate 3 is provided, made of monocrystalline silicon carbide of low crystal quality, with a diameter of 150 mm and a thickness of 550 μm.

[0132] A cleaning sequence of RCA type + Caro's acid is applied to the donor substrate 11 and the carrier substrate 3 to remove possible contaminants from the free surfaces of the donor substrate 11 and the carrier substrate 3.

[0133] To form the first film 21 and the second film 22, tungsten is deposited on the front surface 11a of the donor substrate 11 and on the front surface 3a of the carrier substrate 3 using chemical vapor deposition at a temperature of around 700° C. with a thickness of 0.5 nm (step d)).

[0134] In order to achieve an implantation peak (maximum concentration) in the film 21, nitrogen is implanted at an implantation energy of 5 keV and E 16 / cm 2 is implanted into the film 21 of the donor substrate 11 (Step-1).

[0135] Next, step e) provides for the bonding by molecular adhesion of the implanted film 21 of the donor substrate 11 to the film 22 of the carrier substrate 3 along the bonding interface 4 to form a stack 311. The two films 21, 22 form the intermediate layer 2.

[0136] The separation step f) is performed by applying a heat treatment at 950° C. for several tens of minutes or even an hour along the buried weak plane 5. In this way, a temporary substrate 10 with a surface modified layer 1 is formed. The remaining part of the donor substrate 11′ may be reconditioned and reused in a new cycle.

[0137] A step of chemical mechanical polishing is also carried out, which removes about 200 nm from the surface of the worked layer 1, as well as a heat treatment at a temperature above 1000° C. Most of the atoms 2a of the gaseous species are kept trapped in the intermediate layer 2 during this step.

[0138] For the purpose of transferring the working layer 1 to the receiver substrate 50 to produce the composite structure 51, a step of LP-CVD deposition of polycrystalline silicon carbide is carried out on the working layer 1 of the temporary substrate 10 using methylsilane precursor at a temperature of 1250° C. for 120 minutes so that the thickness of the receiver substrate 50 reaches 360 μm. The receiver substrate 50 is polycrystalline under these conditions (step g)) of very high quality. A grinding and / or polishing step can be carried out to adjust the thickness of the receiver substrate 50 and possibly the shape of the periphery of the receiver substrate 50. In this way, a releasable structure 510 is produced.

[0139] The peeling step h) corresponds to a heat treatment at 1700 ° C. applied to the peelable structure 510. A peeling interface is formed in the intermediate layer 2, caused by diffusion of the nitrogen atoms 2a trapped in the intermediate layer 2 and their accumulation at or very close to the bonding interface 4 to form pressurized microcracks, until it causes a complete peeling of the peelable structure 510. In this way, a composite structure 51 is obtained, on the one hand, comprising the working layer 1 arranged on the receiver substrate 50, and, on the other hand, a carrier substrate 3. The composite structure 51 and the carrier substrate 3 each comprise residues 2', 2'' of the intermediate layer 2, which can be removed, for example, by grinding or chemical etching.

[0140] If mechanical grinding or chemical-mechanical polishing has not been performed on the releasable structure 510, it is preferably performed on the rear surface of the composite structure 51.

[0141] In principle, the front surface 51a of the structure 51, which corresponds to the free surface 51a of the working layer 1, does not require conventional cleaning due to the quality of the layer of the temporary substrate 10 and the low roughness of the front surface 51a obtained.

[0142] Vertical components may then be manufactured on the composite structure 51 , possibly after epitaxial growth of additional layers on the working layer 1 .

[0143] Under conditions similar to those described in the above example, the material of at least one film 21, 22 may be amorphous silicon and the atoms 2a introduced may be argon or helium.

[0144] Of course, the invention is not limited to the embodiments and examples described, and variations of the implementation may be made to the invention without departing from the scope of the invention, which is defined by the claims.

Claims

1. A temporary substrate (10) that can be peeled off at a peeling temperature exceeding 1000°C, the temporary substrate (10) comprising: A semiconductor processing layer (1) extending along a major plane (x, y); A carrier substrate (3), an intermediate layer (2) arranged between the processing layer (1) and the carrier substrate (3) and having a thickness along an axis (z) perpendicular to the main plane (x, y) of less than 20 nm; a bonding interface (4) located within or adjacent to said intermediate layer (2); Maximum concentration is 10 ２１ / cm ３ and distributed according to a concentration profile (2b) along said axis (z) perpendicular to said main planes (x, y), said atoms (2a) being kept confined in said intermediate layer (2), in adjacent layers of said carrier substrate (3) having a thickness of 10 nm or less, and / or in adjacent sublayers of said processing layer (1) having a thickness of 10 nm or less, when said temporary substrate (10) is exposed to a temperature below said delamination temperature, said atoms (2a) being intended to diffuse to a delamination interface when said temporary substrate (10) is exposed to a temperature above said delamination temperature; A temporary substrate (10).

2. Temporary substrate (10) according to claim 1, wherein said intermediate layer (2) is made of at least one material selected from the group consisting of tungsten, nickel, titanium, aluminium, molybdenum, tantalum, titanium nitride, tantalum nitride and amorphous silicon.

3. Temporary substrate (10) according to claim 1 or 2, wherein said gas species is nitrogen, helium, argon, xenon and / or hydrogen.

4. 4. The temporary substrate (10) according to any one of claims 1 to 3, wherein the carrier substrate (3) comprises a material whose thermal expansion coefficient is equal to or close to the thermal expansion coefficient of the working layer (1).

5. A process for manufacturing a temporary substrate (10) according to any one of claims 1 to 4, said process comprising: a) providing a donor substrate (11); b) implanting the donor substrate (11) with light ions selected from hydrogen, helium or a combination of the two, in order to form a buried weak surface (5) in the donor substrate (11), the buried weak surface (5) defining, together with the front surface (11a) of the donor substrate (11), a surface engineered layer (1); c) providing a carrier substrate (3) having a front surface (3a); d) depositing on said front surface (11a) of said donor substrate (11) and / or on said front surface (3a) of said carrier substrate (3) at least one film (21, 22) intended to form said intermediate layer (2); e) bonding the donor substrate (11) and the carrier substrate (3) such that the at least one film (21, 22) is disposed between the substrates (11), (3) to form the intermediate layer (2); f) separating along said buried weak surface (5) to form, on the one hand, said temporary substrate (10) and, on the other hand, the remaining part of the donor substrate (11'), The manufacturing process comprises: Prior to the depositing step d), from the respective front surface (11a, 3a) of the donor substrate (11) and / or the carrier substrate (3) to a depth of 10 nm or less, into said at least one membrane (21, 22) after depositing step d), or After the separating step f), into said intermediate layer (2), The process for producing a temporary substrate (10), further comprising the step of introducing atoms (2a) of said at least one gaseous species.

6. The process for manufacturing a temporary substrate (10) according to claim 5, wherein step f) comprises a heat treatment at a temperature between 900°C and 1200°C.

7. A process for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 1 to 4 to a receiver substrate (50), comprising the steps of: g) forming a peelable structure (510) comprising a receiver substrate (50) disposed on the working layer (1) of the temporary substrate (10), the forming step including treating at a first temperature of 1000° C. or higher; h) peeling the peelable structure (510) along a peel interface in or adjacent to the intermediate layer (2), said peeling step comprising a heat treatment at a peel temperature higher than said first temperature to form a composite structure (51) comprising the working layer (1) arranged on the receiver substrate (50) on the one hand and the carrier substrate (3) on the other hand; A process for transferring a working layer (1) from a temporary substrate (10), comprising:

8. The process for transferring a working layer (1) from a temporary substrate (10) according to claim 7, wherein step g) comprises depositing the receiver substrate (50) on the free side of the working layer (1) of the temporary substrate (10).

9. 9. Process for transferring a working layer (1) from a temporary substrate (10) according to claim 8, wherein the deposition of the receiver substrate (50) is carried out by thermal or activated chemical vapor deposition, or by evaporation, at a temperature of 1000° C. or higher.

10. Process for transferring a working layer (1) from a temporary substrate (10) according to claim 8 or 9, wherein the receiver substrate (50) formed is made of polycrystalline silicon carbide.

11. A process for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 7 to 10, wherein step h) comprises a heat treatment at a temperature of 1400°C or higher, or even 1500°C or higher.

12. A process for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 7 to 11, comprising a step i) of finishing the composite structure (51), comprising a process of chemical cleaning, chemical etching and / or chemical mechanical polishing of a front surface (51a) of the composite structure (51), which is a free surface of the working layer (1).

13. The process for transferring a working layer (1) from a temporary substrate (10) according to claim 12, wherein step i) comprises a step of chemical cleaning, chemical etching, mechanical grinding and / or chemical-mechanical polishing of the rear surface (50b) of the composite structure (51), which is a free surface of the receiver substrate (50).

14. The process for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 7 to 13, comprising a step g') of treating the releasable structure (510) including a process of chemical cleaning, chemical etching, mechanical grinding and / or chemical-mechanical polishing of the rear surface (50b) of the receiver substrate (50) prior to the peeling step h).

15. A process for transferring a working layer (1) from a temporary substrate (10) according to any one of claims 7 to 14, possibly including a step of manufacturing an electronic component in or on said working layer (1) of said composite structure (51) after epitaxial growth of an additional layer on said working layer (1).

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