Method for fabricating a donor substrate

Abstract

The invention relates to a method for manufacturing a donor substrate, comprising the steps of A: providing a handle substrate, B: providing a target substrate, C: attaching the target substrate to the handle substrate, and D: conditioning, in particular by polishing, the target substrate attached to the handle substrate, to form a donor substrate, characterized in that between steps C and D a waiting period of a predetermined duration is observed.

Description

[Technical field]

[0001] The invention, which forms the subject of the present application, relates to a method for manufacturing a donor substrate, and finds its application in particular in the field of the manufacture of multilayer substrates, such as piezo-on-insulator (POI) or silicon-on-insulator (SOI) substrates. [Background technology]

[0002] It is known in the art to fabricate donor substrates, also called donor virtual substrates (DVS), adapted for the transfer of layers from said donor substrate to a carrier substrate. A DVS typically comprises at least one handle substrate, in particular made of a semiconductor material such as silicon or sapphire, and a target substrate to which its layers are intended to be transferred. DVS are particularly used in the fabrication of multilayer substrates by methods of the SmartCut® type.

[0003] The implementation of DVS for layer transfer has the main advantage of mitigating parasitic mechanical forces that can be induced by thermal expansion differences between the carrier substrate and the layers deposited on it. Thus, by matching the thermal expansion coefficient of the donor substrate to that of the carrier substrate, it is possible to minimize deformations during thermal processing.

[0004] A further advantage of the DVS implementation is in the fabrication ergonomics: each donor substrate can be reused many times in each manufacturing cycle to provide new layers on a new carrier substrate using SmartCut® type methods, which is called a DVS "refresh".

[0005] Thus, FR 1 852 573 A1 discloses a first method for producing donor substrates with good mechanical strength by polymerization of a photopolymerizable adhesive layer, which makes it possible to avoid resorting to high-temperature production steps that are expensive and can lead to bending of the substrate.

[0006] In order to increase the manufacturing yield of multilayer substrates such as POI or SOI, it is conceivable to reduce quality defects that may occur during and at the end of the manufacturing method. In particular, material defects such as cracks or crack initiation, especially at the edge of the substrate, may be observed in the manufactured multilayer substrates. These defects may be caused by DVS and may be transferred or occur on other substrates manufactured by the transfer of layers from a donor substrate to a carrier substrate, for example during the SmartCut® step. The occurrence of quality defects may therefore lead to production scrap in some cases.

[0007] (Objective of the Invention) In view of the above, it is an object of the present invention to provide a method for fabricating a donor substrate which improves the manufacturing quality of the donor substrate and leads to a reduction in the occurrence of defects, in particular the occurrence of defects observed on the final multilayer substrate. Summary of the Invention

[0008] BRIEF DESCRIPTION OF THE DRAWINGS In this regard, the invention relates to a method for fabricating a donor substrate, comprising the steps of A: providing a handle substrate, B: providing a target substrate, C: attaching the target substrate to the handle substrate, including bonding via an adhesive layer, the adhesive layer being a layer of a photopolymerizable material, in particular a layer of a photopolymerizable liquid having a thickness of 3 μm to 8 μm, and D: conditioning the target substrate attached to the handle substrate, in particular by polishing, to form a donor substrate, the method being characterized in that between steps C and D a waiting period of a predetermined duration is observed.

[0009] According to the unexpected findings of the inventors, the implementation of a waiting period of a given duration between steps C and D can result in a significant reduction in the amount of cracks observed in the multilayer substrates produced from the donor substrates produced by the method forming the subject of the present invention. In particular, the waiting period can allow the components of the unconditioned donor substrate to be stationary to improve robustness. In particular, the stabilizing effect of the adhesive layer of photopolymerizable material for attachment in step C can be amplified. The unconditioned donor substrate can thus become more resistant to the mechanical stresses it undergoes during the subsequent conditioning and during the subsequent layer transfer steps. As a result, the proportion of multilayer substrates produced from the donor substrate that have a risk of cracking can be reduced and the overall quality of the production of multilayer substrates can be increased. For example, the surface area or radius of the usable substrate can be increased by reducing the amount of cracks at the edge of the substrate.

[0010] According to one aspect of the invention, the target substrate is a piezoelectric substrate, in particular a piezoelectric substrate comprising a material selected from quartz, lithium tantalate, lithium niobate, aluminum nitride, zinc oxide, gallium orthophosphate, barium titanate, langasite, langanite, gallium nitride, lead zirconate titanate or langatate.

[0011] Therefore, the DVS obtained by this method can be used to fabricate POI substrates. Since piezoelectric substrates are particularly valuable due to their high price and diverse applications, the reduction of manufacturing scrap by the method of the present invention may be even more advantageous.

[0012] According to one aspect of the invention, the handle substrate comprises a material selected from silicon, sapphire, aluminum nitride, silicon carbide, or gallium arsenide.

[0013] By selecting one of these materials, the thermal expansion coefficient of the handle substrate can be suitably matched for the subsequent use of the DVS for the fabrication of multi-layer substrates.

[0014] According to one embodiment of the invention, the predetermined duration is at least 24 hours, preferentially at least 48 hours, preferably at least 105 hours.

[0015] By selecting such a predetermined duration, it is possible to obtain particularly large gains in the quality of the manufactured substrates, for example a crack percentage of 20% or less, 10% or less or 5% or less, respectively, on multilayer substrates obtained from donor substrates produced by the method according to this aspect of the invention.

[0016] According to one aspect of the invention, the predetermined duration is less than 300 hours, preferentially less than 200 hours, preferably less than 150 hours.

[0017] By limiting the duration of the waiting period in this manner, it is possible to maintain a good balance between gains in production quality and decreases in production throughput. According to one aspect of the invention, the predetermined duration is determined as a function of the material of the adhesive layer.

[0018] The waiting period can therefore be adapted to the adhesion and relaxation properties specific to each adhesive layer material, which in particular can make it possible to precisely adapt the waiting period required to obtain a gain in the quality of the manufactured substrate.

[0019] According to one aspect of the invention, the predetermined duration is selected on the basis of a statistical study representing the percentage of cracks observed on a multilayer substrate obtained from a donor substrate produced by the method according to the duration of the waiting period observed, such that said duration corresponds to the duration necessary to obtain a percentage of cracks of 20% or less, in particular 10% or less, or even more particularly 5% or less. In particular, the statistical study can be obtained from a test including at least 500 produced donor substrates, for example in the form of wafers.

[0020] By basing the duration of the waiting period on such statistical studies, it is possible to even more accurately tailor the method to the desired quality targets of the manufactured donor substrates.

[0021] According to one aspect of the invention, the waiting period is observed under ambient conditions, thus avoiding the cost and footprint of environmental control equipment and achieving the benefits of the invention.

[0022] Another object of the invention relates to a method for transferring a layer from a donor substrate to a carrier substrate, comprising the steps of: A: providing a donor substrate obtained by implementing one of the methods described above; B: forming weakened zones in the target substrate so as to delimit the layers of the target substrate to be transferred; C: providing a carrier substrate comprising in particular a material corresponding to the material of the handle substrate; D: attaching the donor substrate to the carrier substrate; and E: breaking and separating the donor substrate along the weakened zones.

[0023] The implementation of this method, as detailed above, can make it possible to obtain a multi-layer substrate with a reduced occurrence of material defects, and by implementing a waiting period of a given duration, the quality of the donor substrate obtained can be increased, so that the layers of the target substrate transferred to the carrier substrate are also of higher quality.

[0024] The combination of the method for fabricating a donor substrate and the method for transferring a layer from a donor substrate is particularly advantageous since it allows the reuse of the broken donor substrate, i.e. the remainder of the donor substrate remaining after step E. Thus, for example in a "refresh" of a SmartCut® type method, the same remainder donor substrate can be prepared for the transfer of another layer of the target substrate to another carrier substrate in a subsequent production cycle.

[0025] The objects, features and advantages of the present invention, outlined above, will be more fully understood and appreciated upon consideration of the following more detailed description of the invention and upon consideration of the accompanying drawings. [Brief description of the drawings]

[0026] [Figure 1] 2A-2D diagrammatically represent successive steps of a method for fabricating a donor substrate according to an embodiment of the present invention; [Diagram 2] 1 diagrammatically represents successive steps of a method for transferring a layer according to one embodiment of the present invention, in which, for greater clarity of the drawing, the illustrated elements are not necessarily shown to scale, either with respect to each other or with respect to their relative Cartesian dimensions; [Diagram 3] 1 shows a graph derived from test results performed in optimizing a manufacturing method.

[0027] Detailed Description of the Drawings One embodiment of a method for fabricating a donor substrate 1 according to the invention will now be described with reference to figure 1. Figure 1 shows diagrammatically the successive steps of the fabrication of a donor substrate 1.

[0028] The method comprises a step E1 of providing a handle substrate 3. The handle substrate 3 may comprise a material selected from silicon (Si), sapphire (Al2O3), aluminium nitride (AlN), silicon carbide (SiC), gallium arsenide (GaAs), quartz (SiO2) or another glass.

[0029] The method comprises a step E2 of providing a target substrate 5. The target substrate 5 is a substrate intended to be subsequently transferred at least in part to a carrier substrate.

[0030] According to one embodiment of the method, the target substrate 5 may be a piezoelectric substrate. For example, the target substrate 5 may be made of LTO (La2Ti2O7), quartz (SiO2), lithium tantalate (LiTaO3), lithium niobate (LiNbO3), aluminum nitride (AlN), zinc oxide (ZnO), gallium orthophosphate (GaPO4), barium titanate (BaTiO3), langasite (La3Ga5SiO4), or a combination of these. 14 ), Langanite (La3Ga 5.5 Nb 0.5 O 14), gallium nitride (GaN), lead zirconate titanate (PZT) or langatate (La3Ga 5.5 Ta 0.5 O 14 ) These materials are particularly suitable for bulk acoustic wave (BAW) or surface acoustic wave (SAW) applications such as POI-based SAW sensors or BAW filters.

[0031] According to another embodiment, the target substrate 5 may be a substrate comprising a semiconductor material such as silicon (Si), sapphire (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), gallium arsenide (GaAs), quartz (SiO2) or another glass.

[0032] In step E3, the target substrate 5 is attached to the handle substrate 3. In this embodiment, the attachment in step E3 is performed by bonding, in particular by bonding with an adhesive layer 7. An adhesive layer of a photopolymerizable material is preferably used. Such a material can polymerize when irradiated with a light beam. By way of example, in this step an adhesive layer 7 with a thickness of 3 μm to 8 μm of the product sold by NORLAND PRODUCTS under the reference "NOA61" can be formed and then subjected to UV radiation through the exposed surface of the target substrate 5 attached to the handle substrate 3.

[0033] According to the invention, in contrast to methods known in the art for the fabrication of a donor substrate, the method is followed by a step E4 during which the fabrication method is interrupted for a waiting period of a predetermined duration, said waiting period being at least 24 hours, preferably 105 hours.

[0034] The waiting period is observed under ambient conditions, i.e. during the waiting the target substrate 5 attached to the handle substrate 3 is kept at ambient temperature, in particular at a temperature between 20° C. and 26° C., and at ambient pressure, in particular at a pressure between 950 hPa and 1030 hPa.

[0035] Finally, the target substrate 5 attached to the handle substrate 3 is subjected to a conditioning step E5. Conditioning is understood to mean a surface treatment aimed at reducing the roughness of the exposed surface 9 of the target substrate 5 attached to the handle substrate 3. Conditioning is preferably carried out by polishing or chemical-mechanical polishing (CMP).

[0036] In one example, the conditioning may include several successive steps of polishing and / or CMP. As a variant, the conditioning may include one or several steps of dry etching, for example reactive ion etching, i.e. RIE according to the English term "reactive ion etching".

[0037] This fabrication method results in a donor substrate that solves the problem of the invention. The use of a handle substrate 3 is suitable for fabricating, for example, SOI or POI substrates, since, in contrast to conventional methods such as epitaxial growth, it makes it possible to avoid deformations induced by high temperatures during thermal treatments.

[0038] The bonding by adhesive layer 7 in step E3 ensures a sufficient mechanical cohesion of the two bonded substrates. By using a photopolymerizable material, the attachment can be carried out without resorting to bonding at high temperatures, for example above 200° C.

[0039] The conditioning in step E5 makes it possible to obtain a surface of uniform planarity that is sufficiently smooth for the subsequent transfer of a layer onto a carrier substrate, for example using a method of the SmartCut® type.

[0040] Surprisingly, the inventors have found that fewer defects are observed if the donor substrate 1 is subjected to a waiting period between the attachment step E3 and the conditioning step E5. This effect is particularly favorable in comparison with multilayer substrates, such as POI or SOI substrates, obtained with a donor substrate 1 produced without observing a waiting period. In particular, the waiting period allows the components of the unconditioned donor substrate 1, i.e. the components of the target substrate 5 attached to the handle substrate 3, to improve their robustness before being subjected to conditioning, in particular before being subjected to a subsequent layer transfer step during the production of a multilayer substrate, such as SOI or POI type, by SmartCut®. The unconditioned donor substrate is thus more resistant to the mechanical stresses it is subjected to during the conditioning step or during the subsequent layer transfer. As a result, the number of produced donor substrates 1 that are prone to defects, in particular cracks, at the end of the transfer of the layers of the target substrate is reduced, and the overall quality of the production is increased.

[0041] A method for transferring a layer from a donor substrate to a carrier substrate according to one embodiment of the present invention will be described with reference to Figure 2. The method described relates to a donor substrate 1 obtained by the method according to Figure 1.

[0042] The method for transferring a layer starts with step E11 of providing a donor substrate 1 resulting from step E4 of the fabrication method according to the embodiment of the invention in FIG.

[0043] Then, in step E12, a weakened zone 11 is formed in the target substrate 5 of the donor substrate 1. The zone 11 is formed so as to delimit a layer 13 of the target substrate 5 to be transferred. The layer 13 is delimited in the target substrate 5 by the weakened zone 11 and the adjustment surface 9. The weakened zone 11 is preferably formed by implantation of ions, for example hydrogen ions or a noble gas such as helium. The amount of ions, the distribution of the amount of ions and the implantation energy of the ions may vary and determine the characteristics of the weakened zone 11 formed. The depth of the weakened zone 11 in the target substrate 5 determines the thickness of the layer 13 to be transferred.

[0044] In step E13, a carrier substrate 15 is provided. The carrier substrate 15 may preferably comprise a material selected from silicon (Si), sapphire (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), gallium arsenide (GaAs), quartz (SiO2) or another glass. The carrier substrate has a main surface 17.

[0045] Preferably, the material of the handle substrate 3 of the donor substrate 1 is selected to have a thermal expansion coefficient value that is equal to or similar to the thermal expansion coefficient value of the carrier substrate 15 onto which the layer 13 is intended to be transferred. Similar coefficient values ​​typically correspond to values ​​of +10% to -10% of a reference value.

[0046] Therefore, in order to obtain suitable thermal expansion coefficient values, the carrier substrate 15 and the handle substrate 3 are preferably made of the same material.

[0047] In step E14, the donor substrate 1 is attached to a carrier substrate 15. The donor substrate 1 is attached by attaching the alignment surface 9 along a main surface 17 of the carrier substrate 15, forming a composite 19.

[0048] The attachment can be performed, for example, by bonding by means of a dielectric layer deposited on at least one of the two surfaces 9, 17 to be bonded. The dielectric layer can be, for example, a layer of glass deposited on the target substrate 5 by centrifugation by the spin-on-glass (SOG) method. The attachment can be strengthened by subjecting the surface to be bonded, on which the dielectric layer is not deposited, to a treatment designed to allow hydrophilic molecular bonding with the surface on which the dielectric layer has subsequently been deposited. The attachment can also be strengthened by a densification thermal annealing operation, for example at a temperature of about 250 ° C. In this case, the parasitic mechanical forces induced by the thermal expansion difference between the carrier substrate 15 and the target substrate 5 are at least partially alleviated by attaching the target substrate 5 to the handle substrate 3, on the side opposite to the carrier substrate 15. The thermal expansion coefficients of the substrates 3, 15 and the target substrate 5 are therefore similar.

[0049] Then, in step E15, the complex 19 of the donor substrate 1 comprising the weakened target substrate 5 attached to the carrier substrate 15 is broken along the weakened zone 11 and separated into two parts, namely a final multilayer substrate 21, such as a POI or SOI substrate comprising the carrier substrate 15 onto which the partitioned layers 13 of the target substrate 5 have been transferred, and the remaining part of the donor substrate after the breaking step, shown as broken donor substrate 23.

[0050] The broken donor substrate 23 can be restored or "refreshed" in order to be subjected again to step E12 for forming the weakened zones 11. Steps E12, E13, E14 and E15 can therefore be repeated many times on the basis of a single original donor substrate 1 provided in order to manufacture several final multilayer substrates 21, such as POI or SOI substrates. The number of "refreshes" possible on the donor substrate 1 is limited by the thickness of the target substrate 5 of the donor substrate 1 from which a layer 13 is removed in each iteration of the "refresh". In contrast, material defects present in the target substrate 5 of the donor substrate 1 provided in step E11 remain therein or become even more pronounced throughout the method described with reference to FIG. 2. In each cycle, these defects are transferred in step E14 to the carrier substrate 15 via the transferred layer 13. Thus, the overall improvement in the quality of the donor substrate 1 provided in step E11 is directly linked to all products resulting from the method.

[0051] Figure 3 reproduces in graphical form the results of observing cracks on a sample of multilayer substrates 21, e.g. POI or SOI substrates, produced by an embodiment of the method of the invention described above. The sample of Figure 3 comprises 818 donor substrates 1 produced by the method of Figure 1, while observing different waiting periods up to 300 hours in duration. The substrates in the sample comprise a handle substrate 3 made of silicon (Si), a target substrate 5 made of LTO (La2Ti2O7) and an adhesion layer 7 made of NOA61.

[0052] Fig. 3 shows a graph for a sample of a final multilayer substrate 21 after step E15 of the method of Fig. 2 in a first production cycle. The donor substrate 1 from which the sample of substrate 21 was produced has therefore not yet been subjected to a "refresh" in the SmartCut® method. Each point on the graph corresponds to a sample multilayer substrate 21 whose quality, i.e. the presence or absence of material defects, has been observed and recorded depending on the waiting period observed in step E5 of the method for making the donor substrate 1 in step E11.

[0053] Therefore, the tested multilayer board samples are classified and quantified into three groups: without material defects (S), with crack initiation (A), and with cracks (F). Crack initiation is a crack that does not pass completely through the thickness of the board.

[0054] It is therefore possible to determine the percentage free of material defects T_a=S / (S+A+F) and the percentage free of cracks T_b=(S+A) / (S+A+F) depending on the waiting period observed during the fabrication of the donor substrate 1. In Fig. 3 T_a is represented by reference numeral 31 and T_b by reference numeral 33. The curves 31 and 33 representing the percentages T_a and T_b are obtained by non-linear regression of the statistical results of the observations.

[0055] By studying the curves 31 and 33 in Fig. 3, it becomes clear that the longer the duration of the waiting period observed in step E4, the higher the defect-free fraction T_a and crack-free fraction T_b of the produced multilayer substrate. Thus, the longer the waiting period, the higher the quality of the production obtained.

[0056] FIG. 3 generally makes it possible to identify that the rate T_i (=1-T_a) of occurrence of material defects can be reduced by choosing a predetermined duration of at least 24 hours, preferentially at least 48 hours, preferably at least 105 hours. These values ​​make it possible to obtain particularly large gains in the quality of the substrates produced. It is thus possible to read from the graph of FIG. 3 a rate T_a of absence of material defects of the order of 68%, 75% or 81% for these periods of 24 hours, 48 ​​hours and 105 hours, respectively. Furthermore, it is possible to read from the graph of FIG. 3 a rate T_f (=1-T_b) of cracks of the order of 20%, 10% and 5%, respectively, for these periods of 24 hours, 48 ​​hours and 105 hours, as identified by the reference number 35.

[0057] For example, the study makes it possible to read that by observing a waiting period of 105 hours during step E4, a quality gain of 21% is obtained in terms of the level of material defects without observing a waiting period.

[0058] At the same time, it is also clear from the curves 31 and 33 in Fig. 3 that the gain in the quality of the produced donor substrates decreases the longer the observed waiting period. It is preferable not to interrupt the production line and to delay the production of the donor substrates for a time that is not too long. It is therefore preferable to limit the waiting time to a maximum of 300 hours, preferentially a maximum of 200 hours and preferably a maximum of 150 hours. By limiting the duration of the waiting period in this way, it is possible to maintain a good balance between the gain in quality and the slowdown of the production flow.

[0059] According to one variant of the invention, the predetermined duration of step E4 may be selected on the basis of the curve 31 or 33 obtained by a statistical study represented by Fig. 3. For example, a quality target may be set and the duration of the waiting period to be observed may be read off from the curve 31 or 33 in question. For example, to set a quality target for the percentage of cracks at a maximum of 3%, it is sufficient to identify a waiting period corresponding to the value T_b = 97%, which in this example corresponds to a duration of 105 hours. By basing the duration of the waiting period in this way on the results of the study, the method is precisely adapted to the desired quality target.

[0060] Alternatively, the predetermined waiting time in E4 may be determined by analysis of the slope of the curve 31 or 33. For example, a tangent to the curve 31 at time x=0 or a linear extrapolation of the percentage T_a free of material defects between time x=0 and time x=1 may be determined, as shown by reference numeral 39. The tangent 39 may be intersected with an asymptote 41 of the corresponding percentage T_a such that a waiting period of 70 hours is obtained for a T_b value of 90% or a T_a value of 78% of the multilayer substrate 21.

[0061] According to an embodiment described above with reference to FIG. 1, the attachment of the target substrate to the handle substrate comprises a step of bonding by means of an adhesive layer. In this case, it is appropriate to adapt the duration of the waiting period to the adhesive layer material, in particular to the adhesive and relaxation properties specific to the selected adhesive layer material. For example, the selected adhesive layer material may be compared with the attachment mode selected in the reference case to create a comparison factor. The comparison factor can then be used to more accurately adapt the selected duration of the waiting period for the fabrication of the donor substrate. This makes it possible to accurately adapt the waiting period required to obtain a maximum gain in the quality of the manufactured multilayer substrate 21, in particular a POI or SOI substrate.

[0062] Thus, by providing a donor substrate according to the invention, for example a donor substrate 1 obtained by the method described with reference to Fig. 1, the method for transferring layers is also improved and a higher quality multilayer substrate can be provided. For example, using the SmartCut® method it is possible to obtain commercial SOI and POI substrates with a higher yield due to the reduction in material defects observed.

Claims

1. 1. A method for fabricating a donor substrate, comprising: A: Providing a handle substrate (3); B: Providing a target substrate (5); C: A step of attaching the target substrate (5) to the handle substrate (3), including bonding via an adhesive layer (7), the adhesive layer (7) being a layer of photopolymerizable material, in particular a layer of photopolymerizable liquid having a thickness of 3 μm to 8 μm; D: conditioning the target substrate (5) attached to the handle substrate (3), in particular by polishing, to form the donor substrate (1); Including, A method characterized in that a waiting period of a predetermined duration is observed between steps C and D.

2. 2. The method of claim 1, wherein the target substrate (5) is a piezoelectric substrate, in particular a piezoelectric substrate comprising a material selected from quartz, lithium tantalate, lithium niobate, aluminum nitride, zinc oxide, gallium orthophosphate, barium titanate, langasite, langanite, gallium nitride, lead zirconate titanate or langatate.

3. 3. The method according to claim 1 or 2, wherein the handle substrate (3) comprises a material selected from silicon, sapphire, aluminum nitride, silicon carbide or gallium arsenide.

4. 3. The method according to claim 1 or 2, wherein said predetermined duration is at least 24 hours, preferentially at least 48 hours, preferably at least 105 hours.

5. 3. The method according to claim 1 or 2, wherein said predetermined duration is less than 300 hours, preferentially less than 200 hours, preferably less than 150 hours.

6. 3. The method according to claim 1 or 2, wherein the predetermined duration is determined depending on the material of the adhesive layer (7).

7. 3. The method according to claim 1 or 2, wherein the predetermined duration is selected based on statistical studies, in particular studies obtained from tests involving at least 500 donor substrates, and the percentage of cracks observed on a multilayer substrate (21) obtained from the donor substrate (1) is obtained according to the duration of the observed waiting period, such that the predetermined duration corresponds to the duration required to obtain a percentage of cracks of 20% or less, in particular 10% or less, or more particularly 5% or less.

8. 3. The method of claim 1 or 2, wherein the waiting period is observed under ambient conditions.

9. 3. The method of claim 1, wherein step C comprises polymerizing the adhesive layer when irradiated by a light stream.

10. A method for transferring a layer from a donor substrate (1) to a carrier substrate (15), comprising: A: Providing a donor substrate (1) obtained by implementing the method according to claim 1 or 2; B: forming weakened zones (11) in the target substrate (5) so as to delimit the layer (13) of the target substrate (5) to be transferred; C: Providing a carrier substrate (15) comprising a material that corresponds in particular to the material of the handle substrate (3); D: Attaching the donor substrate (1) to the carrier substrate (15); E: Breaking and separating the donor substrate (1) along the weakened zone (11); A method comprising:

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