CN120677124A

CN120677124A - Method for manufacturing a structure comprising a plurality of buried cavities

Info

Publication number: CN120677124A
Application number: CN202480010802.2A
Authority: CN
Inventors: F-X·达尔拉斯; F·马赞
Original assignee: Soitec SA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Soitec SA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2023-03-09
Filing date: 2024-03-05
Publication date: 2025-09-19
Also published as: FR3146544B1; WO2024184336A1; TW202438436A; FR3146544A1

Abstract

The present invention relates to a method for producing a structure comprising a plurality of cavities defined between a thin layer and a carrier substrate, the method comprising the following steps: a) providing a donor substrate and a carrier substrate; b) injecting a first light substance into the donor substrate so as to form a uniform buried weakened plane, which defines, together with the front side of the donor substrate, the thin layer to be transferred; c) locally injecting a second substance into the donor substrate so as to introduce the substance into the uniform buried weakened plane only in a second region, thereby forming a functional buried weakened plane having: a first light substance; a second ... The invention relates to a method for preparing a bonded structure comprising: forming a first region containing a light substance but not containing the second substance, and a second region containing the first light substance and the second substance; d) forming a plurality of cavities opening on the front side of a donor substrate or a carrier substrate; e) assembling the donor substrate onto the carrier substrate along the respective front sides of the donor substrate and the carrier substrate by direct bonding, thereby forming a bonded structure, wherein the cavities are perpendicular to the first region or the second region of the functional buried weakened plane; f) applying a heat treatment to the bonded structure so as to induce spontaneous separation along the functional buried weakened plane and form the structure on the one hand and the remaining portion of the donor substrate on the other hand.

Description

Method for manufacturing a structure comprising a plurality of buried cavities

Technical Field

The present invention relates to the field of microelectronics and electromechanical microsystems. In particular, the present invention relates to a method for collectively manufacturing a plurality of cavities buried in a structure comprising a support substrate and a lamina, the cavities being confined between the support substrate and the lamina.

Background

MEMS devices (MEMS is an acronym for microelectromechanical systems) are widely used for manufacturing various sensors for a variety of applications, for example pressure sensors, microphones, radio frequency switches, electroacoustic and ultrasonic transducers (e.g. piezoelectric micromachined ultrasonic transducers (pmuts)) etc. may be mentioned. Many of these MEMS devices are based on flexible membranes suspended over cavities. In operation, the deflection (deflection) of the membrane associated with a physical parameter (e.g., propagation of an acoustic wave in the case of pMUT) is converted into an electrical signal (and vice versa, depending on whether the device is in receiver or transmitter mode).

There are many layer transfer methods for obtaining structures comprising a thin layer (which will form the above-described film) suspended over a plurality of cavities. These are advantageously based on assembly by direct bonding (i.e. without the addition of adhesive substances) of the donor substrate and the support substrate along their respective front faces. One or the other of the substrates, typically the support substrate, comprises a cavity open on its front face. These cavities are sealed during the assembly step due to molecular adhesion of the two substrates. The step of thinning the donor substrate causes the thin layer to be transferred onto the support substrate. This thinning step may be particularly based on the Smart Cut ^TM technique, which employs a buried plane of weakness formed by the implantation of a light species into the donor substrate, which together with the front side of the donor substrate defines a thin layer (typically having a thickness of less than 2 μm) to be transferred. It is known that by thermal and/or mechanical activation, the growth of microcracks in the buried weakened plane results in a separation along said plane, which causes the transfer of a thin layer onto the supporting substrate. The remainder of the donor substrate may be reused for subsequent layer transfer.

However, it is a complex matter to obtain a high quality transfer of the thin layer due to the presence of the cavity, without hardening effects perpendicular to said cavity. The hardening effect is due here to the presence of the front side of the support substrate in contact with the thin layer.

Thus, the growth of micro-cracks in the buried weakened plane may generate bubbles perpendicular to the cavity or even local spalling, which irreversibly damages the thin layer and corresponds to the transfer defect.

The larger the size of the cavity, the more difficult it is to ensure mass transfer. The target dimension of the lateral dimension of the cavity is typically about a few micrometers to tens of micrometers, which is to maintain a thin layer thickness below 2 μm.

Subject of the invention

The present invention proposes a method for collectively manufacturing a structure comprising a plurality of buried cavities suspended by a high quality thin layer, that is to say a structure exhibiting very few transfer defects. It is based on the formation of buried weakened planes, called functionalities, whose characteristics and properties differ between a first region and a second region, with or without hardening effects, with the aim of de-correlating the maturation of microcracks in these two regions, so as to promote the mass transfer of the layer.

Disclosure of Invention

The present invention relates to a method for manufacturing a structure comprising a plurality of cavities defined between a thin layer and a support substrate, comprising the steps of:

a) Providing a donor substrate and a support substrate, each having a front side and a back side;

b) Injecting a first light species into the donor substrate so as to form a uniform buried weakened plane defining, with the front face of the donor substrate, a thin layer to be transferred;

c) Locally implanting a second substance into the donor substrate so as to introduce the second substance into the uniform buried weakened plane only in a second region so as to form a functional buried weakened plane exhibiting:

-a first zone comprising the first light material but not the second material, and

-A second zone comprising the first light material and the second material;

d) A plurality of cavities formed to be opened on a front surface of the donor substrate or the support substrate;

e) Assembling the donor substrate to the support substrate along the front side of each of the donor substrate and the support substrate by direct bonding to form a bonded structure in which the cavity is perpendicular to the first or second region of the functionally buried weakened plane;

f) A heat treatment is applied to the bonded structure in order to cause spontaneous separation along the plane of functional buried weakness and to form the structure on the one hand and the remainder of the donor substrate on the other hand.

According to an advantageous feature of the invention, alone or according to any achievable combination:

Performing the implantation of step c) in the presence of a mask placed on the front side of the donor substrate;

The formation of the cavities in step d) is carried out by locally etching the front face of the support substrate, for example by means of a mask placed on the front face;

After step c), step d) of forming the cavity comprises etching the front side of the donor substrate perpendicular to the second region, the first region being protected from etching by the mask;

A step c') of locally injecting a third substance on the front side of the donor substrate, after step d) and after removal of the mask, the third substance being thus injected in the first region of the functional buried weakened plane and in a further buried plane located at a distance below the second region of the functional buried weakened plane;

step d) of forming the cavity is performed before step c) and comprises:

o is perpendicular to the second region of the functional buried weakening plane intended to be formed in the following step c), a mask is applied, which mask is placed on the front side of said donor substrate, perpendicular to the second region of the functional buried weakening plane intended to be formed in the following step c), and

O etching the front side of the donor substrate perpendicular to the first region, the second region being protected from etching by the mask;

After step d), and after removing the mask from the front side of the donor substrate, performing an implantation step c), the second substance being thus implanted in the second region of the functional buried weakened plane and in a further buried plane located at a distance below the first region of the functional buried weakened plane;

the second region of the functional buried weakened plane is perpendicular to the cavities in the bonded structure, and the first light species is a hydrogen atom or ion and the second species is a helium atom or ion;

The first region of the functional buried weakened plane is perpendicular to the cavities in the bonding structure, the first light species is a hydrogen atom or ion, or a helium atom or ion, or a hydrogen and helium atom or ion, and the second species is a silicon atom or ion, which is capable of slowing down the growth rate of microcracks (micro-fissure) in the second region of the functional buried weakened plane compared to the growth rate of microcracks in the first region.

The assembly step e) comprises at least one intermediate layer placed on the donor substrate and/or on the support substrate, which intermediate layer has been deposited after one of steps a) to d).

Drawings

Other features and advantages of the present invention will appear from the following detailed description, which refers to the accompanying drawings, in which:

FIG. 1 depicts two structures produced using a manufacturing method according to the present invention;

[ FIG. 2a ]

[ FIG. 2b ]

[ FIG. 2c ]

[ FIG. 2d ]

[ FIG. 2e ]

[ FIG. 2f ]

Fig. 2a to 2f depict steps of a manufacturing method according to a first embodiment of the present invention;

[ FIG. 3a ]

[ FIG. 3b ]

[ FIG. 3c ]

[ FIG. 3d ]

[ FIG. 3e ]

[ FIG. 3f ]

Fig. 3a to 3f depict steps of a manufacturing method according to a second embodiment of the present invention;

[ FIG. 4a ]

[ FIG. 4b ]

[ FIG. 4d ]

[ FIG. 4c ]

[ FIG. 4e ]

[ FIG. 4f ]

Fig. 4a to 4f depict steps of a manufacturing method according to a third embodiment of the present invention, note that in this third embodiment, step d) (fig. 4 d) occurs before step c) (fig. 4 c);

Fig. 5 shows images of an SOI structure with cavities not according to the present invention, as seen from above, obtained after isothermal annealing at different temperatures;

[ FIG. 6a ]

[ FIG. 6b ]

[ FIG. 6c ]

[ FIG. 6d ]

[ FIG. 6c ]

[ FIG. 6e ]

[ FIG. 6f ]

Fig. 6a to 6f depict the steps of a manufacturing method according to a variant of the first embodiment of the invention, note that in this variant an additional step c') is added after step d) compared to the first embodiment shown in fig. 2a to 2 f.

Some of the figures are schematic representations which are not drawn to scale for the sake of legibility. In particular, the thickness of the layer along axis z is not drawn to scale relative to the lateral dimensions along axes x and y. In the drawings, the same reference numerals may be used for elements of the same nature.

Detailed Description

The present invention relates to a method for manufacturing a structure 100, the structure 100 comprising a plurality of cavities 30 defined between a thin layer 10 and a support substrate 20, as shown in fig. 1. The structure 100 may potentially include at least one intermediate layer 50 between the thin layer 10 and the support substrate 20.

The first step a) of the manufacturing method comprises providing a donor substrate 11 and a support substrate 20, from which donor substrate 11 the thin layer 10 is to be transferred (fig. 2a, 3a, 4a, 6 a).

The donor substrate 11 and the support substrate 20 are advantageously in the form of wafers, generally greater than 100mm in diameter, for example 150mm, 200mm or 300mm, and each have a front face 11a, 20a and a back face 11b, 20b. Their thickness is typically between 200 and 900 microns.

The donor substrate 11 may be formed of at least one material selected from silicon, germanium, a III-V semiconductor compound, silicon carbide, lithium tantalate, lithium niobate, or some other material of interest for the target application. The support substrate 20 may be formed of at least one material selected from silicon, germanium, a III-V semiconductor compound, silicon carbide, lithium tantalate, lithium niobate, glass, ceramic, or some other material of interest for the target application.

The next step b) of the method corresponds to the implantation of a first light species (or in other words a full surface or "full wafer" implantation) in the donor substrate 11 through the whole front face 11a of the donor substrate 11, so as to form a uniform buried weakened plane 12', which uniform buried weakened plane 12' defines, together with said front face 11a, the thin layer 10 to be transferred (fig. 2b, 3b, 4b, 6 b). The term "uniform" means herein that the implantation characteristics are the same throughout the buried weakened plane 12'.

These light species may notably be selected from hydrogen and/or helium atoms or ions. As is known with reference to the SmartCut ^TM process, these first species, once injected into the donor substrate 11, are able to form lenticular defects in the uniform buried weakened plane 12', which tend to propagate (spread) in the form of thermally activated microcracks by diffusion of the optical species and coalescence of the lenticular defects. Bearing in mind that the lenticular defects are distributed in a thin layer buried within the donor substrate 11 and defined by an injected gaussian distribution, this layer is called for simplicity a buried weakening plane.

The implantation energy defines the depth that will create a uniform buried weakened plane 12' in the donor substrate 11. For a given implantation energy and a given material of the donor substrate 11, the implantation dose of the light species is an essential parameter defining the microcrack propagation rate, namely the bubbling rate (without reinforcement) and the cracking rate (with reinforcement).

The applicant has determined that in order to obtain a high quality transfer of the lamina 10, in a structure 100 with cavities, the desired characteristics and properties of the buried weakened plane vary according to whether said plane is perpendicular to the area benefiting from the hardening effect or perpendicular to the cavity (and therefore without hardening effect). In the region benefiting from the hardening effect, it seems advantageous to "slow down" the fracture rate, so as to allow the use of relatively high temperatures in the heat treatment, which aim at causing spontaneous separation in the buried weakened plane, while maintaining a controlled treatment time, higher temperatures also allow the microcracks to be placed under greater pressure and promote the continuity of the fracture wave. In areas (perpendicular to the cavity) that do not benefit from the hardening effect, the propagation of microcracks during the above heat treatment is advantageous, producing blisters of large size without premature local flaking.

The progress towards this aim is achieved by implementing a manufacturing method according to the invention which envisages creating a functional buried weakened plane 12, the functional buried weakened plane 12 comprising a first zone Z1, the first zone Z1 being different from the second zone Z2 in terms of dose and/or nature of the implanted species.

Step c) of the method corresponds to locally injecting a second substance into the donor substrate 11, so that said second substance is introduced into the uniform buried weakened plane 12' only in the second zone Z2. This makes it possible to form a functional buried weakened plane 12 (fig. 2c, 3c, 4c, 6 c). The latter plane then has, in the plane (x, y) of the front face 11 a:

A first zone Z1 containing a first light material and no second material, and

-A second zone Z2 comprising a first light mass and a second mass.

The second substance may have the same properties as the first substance or have different properties. The implantation energy for introducing the second species is adjusted such that their implantation profile substantially overlaps with the implantation profile of the first light species. Advantageously, the maximum of the implantation profile of the first species and the second species is located at a depth equal to within +/-20%, or more advantageously, equal to within +/-10%.

The local implantation may be obtained in different ways. The first option (fig. 2c, 3 c) implemented in the first and second embodiments of the invention consists in using a mask (M) applied to the front face 11a of the donor substrate 11 in order to protect the first zone Z1 from implantation. Such masks are typically formed using deposition, photolithography, and etching techniques. Referring to the third embodiment of the invention, another option shown in fig. 4c is to exploit the relief difference on the front face 11a between the area perpendicular to the first area Z1 and the area perpendicular to the second area Z2 in order to locate the second substance in the second area Z2 of the functionally buried weakened plane 12 and introduce them into another but discontinuous buried plane 12″ at a distance below the first area of said plane 12. The second substance may then contribute to the characteristics and properties of the second zone Z2, but not (or only to a very limited extent) to the characteristics and properties of the first zone Z1.

During step d) of the method, a plurality of cavities 30 are formed at the front face 11a of the donor substrate 11 (first and third embodiments, fig. 2d, 6d and 4 d) or the front face 20a of the support substrate 20 (second embodiment, fig. 3 d).

It is important to note that step d) may be performed after step c) (first embodiment, fig. 2d, fig. 6 d) or before step c) (third embodiment, fig. 4 d), or even in parallel with step c) (second embodiment, fig. 3 d).

The formation of the cavity in one of the substrates is conventionally performed by means of a partial etching of the front faces 11a, 20a, for example by means of a mask (M, M') placed on said front faces 11a, 20 a.

The depth of the cavity 30 may typically vary between 100nm and 100 μm. Their shape in the plane (x, y) of the front face 11a, 20a of the relevant substrate 11, 20 may be circular, square, rectangular or polygonal. The characteristic dimension (or transverse dimension) of the cavity 30 in the plane (x, y), i.e. its diameter (in the case of a circular shape) or its side length (in the case of a square shape) or its width and length (in the case of a rectangular shape), is typically 1 μm to 500 μm. The spacing between the cavities 30 may be 1 μm to several hundred mm.

It is envisaged that the first and third embodiments of forming the cavity 30 (fig. 2d, 4 d) in the donor substrate 11 provide the advantage that only one mask (M) is required to perform steps c) and d). However, these embodiments limit the range of possible cavity depths, as the depth needs to remain less than the difference between the depth of the functional buried weakened plane 12 and the target thickness of the thin layer 10 to be transferred.

The second embodiment envisages the formation of a cavity 30 in the support substrate 20 (figure 3 d). In this case, the mask M' for defining the position of the cavity 30 in the substrate 20 and the mask M defining the position defining the first zone Z1 and the second zone Z2 must allow the cavity 30 and the first zone Z1 or the second zone Z2 to correspond to each other during a later assembly step.

The manufacturing method next comprises a step e) of assembling by directly bonding the donor substrate 11 to the support substrate 20 at the respective front faces 11a, 20a of the donor substrate 11 and the support substrate 20 so as to form a bonded structure 90 (fig. 2e, 3e, 4e, 6 e). A bonding interface 40 without adhesive substance is defined between the two assembly faces.

Depending on the embodiment, the cavity 30 is perpendicular to the first zone Z1 or the second zone Z2 of the functional buried weakened plane 12.

The principle of direct bonding is well known in the art and will not be described in detail here. Because it is based on molecular adhesion between the assembly faces, a very good surface finish (cleanliness, low roughness, etc.) of the substrates 11, 20 is required in order to obtain a good quality assembly.

Prior to assembly, the donor substrate 11 and the support substrate 20 typically undergo preparation. For example, conventional processes used in microelectronics, particularly for silicon-based substrates, include ozone cleaning, SC1 cleaning (SC 1 is an acronym for standard cleaning 1) and SC2 cleaning (SC 2 is an acronym for standard cleaning 2), and intermediate rinsing. The surfaces to be assembled may also be activated prior to contact, for example using a plasma, to promote high bonding energy between the surfaces.

Optionally, the donor substrate 11 and/or the support substrate 20 may include an intermediate layer 50 at least on their respective front faces 11a, 20a to facilitate mass bonding and bonding energy at their interfaces, or to suit the purpose of the application (fig. 2e, 3e, 4e, 6 e). The intermediate layer may in particular be formed from an insulating material, such as silicon oxide, silicon nitride or the like. In the particular case where the donor substrate 11 and the support substrate 20 are made of silicon, the structure 100 obtained in the result of this method is then an SOI (silicon on insulator) structure with buried cavities 30.

After one of the steps a) to d) of the method, the intermediate layer 50 located on the donor substrate 11 and/or the support substrate 20 can be formed by growth or deposition.

The direct bonding of step e) may be performed in an ambient atmosphere or in a controlled atmosphere (e.g. in a low pressure chamber).

The next step f) of the manufacturing method corresponds to the application of a heat treatment to the bonded structure 90 in order to cause spontaneous detachment along the functionally buried weakened plane 12 and, on the one hand, to form the structure 100 and, on the other hand, to form the remainder of the donor substrate 11' (fig. 2f, 3f, 4f, 6 f). The structure 100 includes a thin layer 10 and buried cavities 30, the thin layer 10 being assembled with the support substrate 20 along the bonding interface 40, either directly or via an intermediate layer 50.

As previously mentioned, the applicant has determined that by applying a higher separation temperature, the transfer quality of the thin layer 10 of the donor substrate 11 to the support substrate 20 is improved. Fig. 5 shows an image of a portion of the surface of a plurality of SOI structures (not according to the present invention) having cavities for various heat treatment temperatures (isothermal anneals) between 350 ℃ and 450 ℃ after transfer. It is apparent that the density of transfer defects (shown in black in the image) decreases with increasing heat treatment temperature in step f).

In the manufacturing method according to the invention, the functional buried weakened plane 12 consists of two zones Z1, Z2 with different injection characteristics, so that on the one hand it is possible to promote transfer rates compatible with "high" temperatures (in the zones benefiting from the hardening effect) and on the other hand it is possible to promote the formation of large-sized bubbles at these temperatures, with the possibility of having minimal localized flaking (in the zones perpendicular to the cavities 30 that do not benefit from the hardening effect).

According to one embodiment, the second zone Z2 of the functionally buried weakened plane 12 is perpendicular to the cavities 30 in the bonded structure 90.

In the particular case of the SOI-type target structure 100 having a cavity, the first light species may be hydrogen atoms or ions and the second species may be helium atoms or ions. In practice, the donor substrate 11 is thus made of monocrystalline silicon, the support substrate 20 is made of silicon, and an intermediate layer 50 of silicon oxide (for example 200nm in thickness) is located on all or part of one and/or the other of the front faces 11a, 20a before assembly. For example, the cavity 30 is made in the donor substrate 11 and has a depth of 100nm, a lateral dimension of 40 μm and a pitch of 7 μm. The first light species (hydrogen) was implanted at an energy of 140keV at a dose of 6 ^E16/cm² and the second species (helium) was implanted at an energy of 220keV at a dose of 2 ^E16/cm².

The first zone Z1 of the functional buried weakened plane 12, which contains only hydrogen species, is perpendicular to the zone benefiting from the hardening effect, where the implantation characteristics in the first zone Z1 favour the transfer in a higher temperature range (generally equal to 450 ℃ or higher).

The second zone Z2 of the functionally buried weakened plane 12 containing the first substance (hydrogen) and the second substance (helium) is perpendicular to the zone (cavity 30) that does not benefit from the hardening effect, where the implantation characteristics in the second zone Z2 favour the formation of large-sized bubbles in the above-mentioned "high" temperature range.

According to another embodiment, the first zone Z1 of the functionally buried weakened plane 12 is perpendicular to the cavities 30 in the bonded structure 90.

In the particular case of a target structure 100 of SOI type with a cavity, the first light species may be hydrogen atoms or ions, or helium atoms or ions, or hydrogen and helium atoms or ions (and step c), then co-implantation will be involved, i.e. two consecutive implants of the two light species. The locally injected second species are atoms or ions that are able to slow the growth rate of micro-cracks in the second region Z2 of the functionally buried weakened plane 12 compared to the growth rate of micro-cracks in the first region Z1. These second species may be, for example, silicon atoms or ions, which will damage the material of the donor structure 11 to such an extent that a greater or lesser degree of amorphization is achieved, thereby altering the growth rate of microcracks. Of course, a second substance of a different nature may be implanted to achieve the same purpose.

In practice, before assembly, the donor substrate 11 is made of monocrystalline silicon, the support substrate 20 is made of silicon, and an intermediate layer 50 of silicon oxide (for example 200nm thick) is located above the front face 20 a. For example, the cavity 30 is made in the donor substrate 11 and has a depth of 100nm, a lateral dimension of 40 μm and a pitch of 7 μm. The first light species (co-implanted hydrogen and helium) were implanted at energies of 32keV (H) and 52keV (He), at doses of 1 ^E16/cm² and 1.5 ^E16/cm², respectively, and the second species (Si) was implanted at an energy of 360keV, at a dose of 10 ^E14/cm².

The first zone Z1 of the functionally buried weakened plane 12, which contains only the first species (hydrogen and helium), is perpendicular to the zone (cavity 30) that does not benefit from the hardening effect, where the implantation characteristics in the first zone Z1 favour the formation of large-sized bubbles in the "high" temperature range required for the separation heat treatment step f), and possibly with limited local stripping.

The second region Z2 of the functional buried weakened plane 12 containing the first species (hydrogen and helium) and the second species (Si) is perpendicular to the region benefiting from the hardening effect, where the implantation characteristics in the second region Z2 favour the transfer in a "high" temperature range (typically equal to 450 ℃ or higher).

Note that the manufacturing method may include the conventional step of finishing and/or polishing the free surface 10a of the lamina 10 (whether mechanical, chemico-mechanical, chemical or thermal) after step f) in order to achieve the desired crystal quality and surface finish of the lamina 10 in the finished structure 100.

According to a variant of the first embodiment of the invention illustrated in fig. 6a to 6f, a step c') of locally injecting a third substance in the front face 11a of the donor substrate 11 can be carried out. This step c ') may particularly take place after step d) of forming the cavities 30 in the donor substrate 11 and after removal of the mask M (fig. 6 c'). Thus, the third substance is injected into the first zone Z1 of the functional buried weak plane 12 and into another but discontinuous buried plane 12″ located at a distance below the second zone Z2 of the functional buried weak plane 12. These third substances contribute to changing the characteristics and properties of the first zone Z1 of the functional buried weakened plane 12, but have little effect on the characteristics and properties of the second zone Z2.

At the end of the transfer of the thin layer 10, a discontinuous buried plane 12 "is located in the rest of the donor substrate 11' (fig. 6 f).

The present invention may be used in a wide range of MEMS or NEMS (nano-electromechanical systems) devices or any other application for benefiting from a thin layer 10 that is placed locally over a cavity 30 within a structure 100. As already mentioned in this specification, an SOI (silicon on insulator) substrate with buried cavities is a known example of such a structure 100.

The invention is not limited to the described embodiments and may be applied in modified embodiments without departing from the scope of the invention, such as defined by the claims.

Claims

1. A method of manufacturing a structure (100) comprising a plurality of cavities (30) defined between a thin layer (10) and a support substrate (20), the method comprising the steps of:

a) Providing a donor substrate (11) and a support substrate (20), the donor substrate (11) and the support substrate (20) each having a front side (11 a, 20 a) and a back side (11 b, 20 b);

b) -injecting a first light substance into the donor substrate (11) so as to form a uniform buried weakened plane (12 '), the uniform buried weakened plane (12') delimiting, together with the front face (11 a) of the donor substrate (11), a thin layer (10) to be transferred;

c) -locally injecting a second substance into the donor substrate (11) so as to introduce the second substance into the uniform buried weakened plane (12') only in a second zone (Z2), thereby forming a functional buried weakened plane (12), the functional buried weakened plane (12) exhibiting:

-a first zone (Z1) comprising the first light matter but not the second matter, and

-A second zone (Z2) comprising the first light matter and the second matter;

d) A plurality of cavities (30) formed on the front surface (11 a, 20 a) of the donor substrate (11) or the support substrate (20) and opening;

e) -assembling the donor substrate (11) onto the support substrate (20) along the front faces (11 a, 20 a) of the respective donor substrate (11) and support substrate (20) by direct bonding, so as to form a bonded structure (90), in which bonded structure (90) the cavity (30) is perpendicular to the first zone (Z1) or the second zone (Z2) of the functionally buried weakened plane (12);

f) -applying a heat treatment to the bonded structure (90) so as to cause spontaneous detachment along the functionally buried weakened plane (12), and-forming the structure (100) on the one hand, and the remainder (11') of the donor substrate on the other hand.

2. Manufacturing method according to claim 1, wherein the implantation of step c) is performed in the presence of a mask (M) placed on the front face (11 a) of the donor substrate (11), perpendicular to the first zone (Z1) of the functional buried weakening plane (12).

3. The manufacturing method according to claim 2, wherein the formation of the cavities (30) in step d) is performed by locally etching the front face (20 a) of the support substrate (20), for example by means of a mask (M') placed on the front face (20 a).

4. The method of manufacturing according to claim 2, wherein, after step c), step d) of forming the cavity (30) comprises etching the front face (11 a) of the donor substrate (11) perpendicular to the second region (Z2), the first region (Z1) being protected from etching by the mask (M).

5. The method of manufacturing according to claim 4, comprising a step c') of locally implanting a third substance on the front face (11 a) of the donor substrate (11) after step d) and after removal of the mask (M), the third substance being thus implanted in the first region (Z1) of the functional buried weakened plane (12) and in a further buried plane (12 "), the further buried plane (12") being located at a distance below the second region (Z2) of the functional buried weakened plane (12).

6. The manufacturing method according to claim 1, wherein step d) of forming the cavity (30) is performed before step c), and comprises:

-applying a mask (M) perpendicular to a second zone (Z2) of a functional buried weakening plane (12) intended to be formed in a subsequent step c), the mask (M) being placed on the front face (11 a) of the donor substrate (11), and

-Etching the front face (11 a) of the donor substrate (11) perpendicular to the first zone (Z1), the second zone (Z2) being protected from etching by the mask (M).

7. The manufacturing method according to claim 6, wherein, after step d) and after removal of the mask (M) from the front side (11 a) of the donor substrate (11), an implantation step c) is performed, the second substance being thus implanted in the second region of the functionally buried weakened plane (12) and in a further buried plane (12 "), the further buried plane (12") being located at a distance below the first region (Z1) of the functionally buried weakened plane (12).

8. The manufacturing method according to any one of claims 1 to 5, wherein:

-the second zone (Z2) of the functionally buried weakened plane (12) is perpendicular to the cavities (30) in the bonding structure (90), and

-The first light species is a hydrogen atom or ion and the second species is a helium atom or ion.

9. The manufacturing method according to one of claims 1,2, 3, 6, and 7, wherein:

-the first zone (Z1) of the functionally buried weakened plane (12) is perpendicular to the cavities (30) in the bonding structure (90),

-The first light matter is a hydrogen atom or ion, or a helium atom or ion, or hydrogen and helium atoms or ions, and

-The second substance is a silicon atom or ion capable of slowing down the growth rate of micro-cracks in the second zone (Z2) of the functional buried weakening plane (12) compared to the growth rate of micro-cracks in the first zone (Z1).

10. The manufacturing method according to one of claims 1 to 9, wherein the assembly step e) comprises at least one intermediate layer (50) placed on the donor substrate (11) and/or on the support substrate (20), the intermediate layer (50) having been deposited after one of steps a) to d).