Method for manufacturing a substrate comprising a plurality of tiles

Abstract

The invention relates to a method for manufacturing a substrate (100), called donor dummy substrate, comprising a plurality of patches (1) arranged at a distance from each other on a carrier substrate (3), said method comprising the steps of: - arranging patches (1) and an intermediate substrate (2) comprising a plurality of through openings (20) on the carrier substrate (3) such that each patch (1) extends into a respective through opening (20) of the intermediate substrate, and - performing a chemical mechanical polishing on the patches (1) arranged in the openings of the intermediate substrate.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a substrate, the substrate being referred to as a pseudo-donor substrate, the substrate comprising a plurality of wafers, and a method for transferring a chip taken from the wafers to a recipient substrate. Background Technology

[0002] In the fields of microelectronics, optics, or optoelectronics, the design of multilayer structures sometimes requires transferring pieces of a layer in the form of a donor substrate onto a carrier substrate or acceptor substrate.

[0003] This type of process is often referred to as a tiling process and involves the partial transfer of layers taken from a donor substrate to form one or more pieces arranged in a pattern or predetermined position on a carrier substrate.

[0004] This patching may be necessary due to the dimensional differences between the donor substrate and the carrier substrate. Specifically, due to these dimensional differences, it is not possible to transfer a layer of the donor substrate covering the entire surface of the carrier substrate.

[0005] One well-known layer transfer process is Smart Cut. TM The process, in this Smart Cut TM In this process, a weakened region defining the layer to be transferred is formed by seeding atomic particles into a donor substrate; the donor substrate is bonded to a carrier substrate, and the donor substrate separates along the weakened region to transfer the layer from the donor substrate to the carrier substrate. However, this process assumes that the donor substrate and the carrier substrate have the same dimensions.

[0006] While silicon substrates can have relatively large dimensions, typically 300 mm in diameter, other materials of current interest exist only in the form of smaller, bulk substrates, such as 10 cm or 15 cm in diameter. Furthermore, these materials of interest are sometimes particularly expensive, thus minimizing potential waste generated during transfer is desirable. This is especially true for III-V semiconductor materials, which include nitrides (e.g., indium nitride (InN), gallium nitride (GaN), and aluminum nitride (AlN) in binary compounds), arsenides (e.g., indium arsenide (InAs), gallium arsenide (GaAs), and aluminum arsenide (AlAs) in binary compounds) and phosphides (e.g., indium phosphide (InP), gallium phosphide (GaP), and aluminum phosphide (AlP) in binary compounds).

[0007] Based on Smart Cut TMThe solution to the process is not to transfer the entire layer of the donor substrate, but consists of the following steps: taking one or more pieces from at least one donor substrate and transferring the pieces onto an intermediate support to form a so-called pseudo-donor substrate; forming a weakening region in each piece by implanting atomic seeds; bonding the pseudo-donor substrate to the acceptor substrate via the pieces; and separating the individual pieces along the weakening region in order to transfer a portion of each piece to the acceptor substrate.

[0008] For the dummy donor substrate to bond with the acceptor substrate, the free surfaces of the sheet assembly must extend in the same plane. To this end, chemical mechanical polishing (CMP) can be performed prior to bonding, preferably before mechanical abrasion (grinding) of the dummy donor substrate. CMP combines the mechanical action of the polishing pad with the chemical action of the polishing solution to planarize the surface of the sheet assembly.

[0009] However, if the distance between the wafers is large, typically greater than or equal to 250 μm, the polishing pad, which has a degree of flexibility, partially intrudes into the gaps between the wafers, thereby eroding the edges of the wafers. This edge rounding reduces the usable surface area of ​​the chip transferred to the acceptor substrate. Conversely, sharp edges of the wafers cause the polishing pad to degrade very rapidly, thus requiring frequent replacement. Summary of the Invention

[0010] Therefore, the object of the present invention is to create a method that allows the fabrication of pseudo-donor substrates that do not round the edges of the sheets, even when the sheets are spaced apart from each other.

[0011] Therefore, the present invention proposes a method for manufacturing a substrate, referred to as a pseudo-donor substrate, the substrate comprising a plurality of sheets arranged spaced apart from each other on a carrier substrate, the method comprising the following steps: - The sheet and an intermediate substrate are placed on the carrier substrate, the intermediate substrate including a plurality of through openings such that each sheet extends into a corresponding through opening in the intermediate substrate, and - The sheet disposed in the opening of the intermediate substrate is subjected to chemical mechanical polishing.

[0012] The intermediate substrate is made of a material different from the sheet material, or of a material with a similar composition to the sheet but of lower quality.

[0013] The use of an intermediate substrate allows for protection of the sheet edges during chemical mechanical polishing. This prevents the rounding of sheet edges (i.e., corner rounding).

[0014] Depending on other advantageous but optional features, when this is technically possible, the following combinations may be made: - The distance between two adjacent pieces is greater than or equal to 1 mm, preferably greater than or equal to 2 mm; - The distance between each piece and the edge of the corresponding through opening is less than or equal to 250 μm, preferably less than or equal to 100 μm; - The wafer comprises a semiconductor material, such as a III-V group material; - The intermediate substrate is formed by cutting an opening through the silicon or silicon oxide substrate (especially by means of a laser or water jet); - The intermediate substrate is formed by an additive manufacturing process; - The intermediate substrate is formed of a semiconductor substrate, which is bonded to the processing substrate via a dielectric layer, and the opening is formed by selectively etching the semiconductor material down to the dielectric layer; - The thickness of the intermediate substrate is less than or equal to the thickness of the sheet; - The method includes removing the intermediate substrate after performing the chemical mechanical polishing; - The method includes forming weakened regions in the wafers to define corresponding chips in each wafer; - The sheet is placed on the carrier substrate before the intermediate substrate; - The intermediate substrate is placed on the carrier substrate before the sheet.

[0015] The pseudo-donor substrate that can be obtained by the above method includes a carrier substrate, a plurality of pieces arranged at intervals on the carrier substrate, and an intermediate substrate having a plurality of through openings. The intermediate substrate is arranged on the carrier substrate such that each piece is placed in a corresponding through opening, and the free surface of each piece is flush with the surface of the intermediate substrate.

[0016] Based on the advantageous properties of the substrate: - The distance between two adjacent pieces is greater than or equal to 1 mm, preferably greater than or equal to 2 mm; - The distance between each piece and the edge of the corresponding through opening is less than or equal to 250 µm, preferably less than or equal to 100 µm; - The wafer comprises semiconductor materials, such as III-V group materials.

[0017] According to another aspect, the present invention provides a method for transferring a chip to a recipient substrate. The method includes the following steps: - Use the above method to form a pseudo-donor substrate. - The dummy donor substrate is bonded to the acceptor substrate via the said sheet, and - Separate individual chips along the weakened region to transfer each chip to the acceptor substrate. Attached Figure Description

[0018] Referring to the accompanying drawings, other features and advantages of the invention will become apparent from the following detailed description, wherein: - Figure 1 A top view and a cross-sectional view of a pseudo-donor substrate according to one embodiment of the present invention are shown; - Figure 2 Examples are shown in Figure 1 Top view and cross-sectional view of the intermediate substrate used in the pseudo-donor substrate; - Figures 3A to 3D The steps of a first embodiment of a method for manufacturing a dummy donor substrate are illustrated, wherein... Figure 2 The intermediate substrate is mounted on the carrier substrate before the pieces are positioned; - Figures 4A to 4E The steps of a second embodiment of a method for manufacturing a dummy donor substrate are illustrated, wherein... Figure 2 The intermediate substrate is mounted on the carrier substrate after the pieces have been positioned; - Figure 5 The illustration schematically illustrates the formation of weakened regions within a patch; - Figure 6 This schematically illustrates the source from Figure 5 The combination of pseudo-donor substrate and acceptor substrate; - Figure 7 It is a cross-sectional view of the final structure of the chip, including the transfer to the acceptor substrate.

[0019] To make the accompanying drawings clearer, the individual components are not necessarily shown to scale. Detailed Implementation

[0020] The pseudo-donor substrate comprises a sheet of material of interest disposed in a through opening in an intermediate substrate, the sheet and the intermediate substrate extending on a carrier substrate.

[0021] The assembly of the sheet and the intermediate substrate has a free surface that extends in the same plane parallel to the main surface of the carrier substrate. In other words, the surface of the sheet is flush with the surface of the intermediate substrate.

[0022] The function of the intermediate substrate is to at least partially fill the gaps between the wafers. Therefore, by increasing the coverage of the wafers and intermediate substrate over the carrier substrate, the polishing pad can be kept in the plane of the free surface of the wafers and its intrusion between the wafers can be prevented. Thus, edge rounding of the wafers can be avoided or at least minimized.

[0023] Using such an intermediate substrate is particularly advantageous when the distance between two adjacent pieces is greater than or equal to 1 mm, and more preferably greater than or equal to 2 mm.

[0024] The size of the opening is selected based on the size of the sheet, such that the distance between the sheet and the edge of the through opening in which the sheet is arranged is less than or equal to 250 µm, preferably less than or equal to 100 µm. Therefore, even if the polishing pad is flexible, it cannot significantly penetrate between the sheet and the intermediate substrate. Thus, the polishing action is confined to the free surface of the sheet and does not result in rounding of the sheet edges.

[0025] Furthermore, this distance between adjacent sheets and between the sheets and the edges of the corresponding through-holes allows for sufficient material between the openings, thereby ensuring adequate mechanical strength of the intermediate substrate.

[0026] The slabs are typically made of expensive materials that are only available in small sizes. In some cases, the slabs may consist of stacks of such materials.

[0027] The sheet may advantageously include at least one of the materials: - Semiconductor materials, such as group III-V materials, especially indium nitride (InN), gallium nitride (GaN), aluminum nitride (AlN), indium arsenide (InAs), gallium arsenide (GaAs), aluminum arsenide (AlAs), indium phosphide (InP), gallium phosphide (GaP), or aluminum phosphide (AlP), or group IV or group IV-IV materials, especially germanium or silicon carbide (SiC). - Piezoelectric materials, such as lithium tantalate (LiTaO3), lithium niobate (LiNbO3), and potassium sodium niobate (K). x Na 1-x NbO3 or KNN), barium titanate (BaTiO3), quartz, lead zirconate titanate (PZT), magnesium lead niobate and lead titanate compounds (PMN-PT), zinc oxide (ZnO), aluminum nitride (AlN) or scandium aluminum nitride (AlScN), and / or - Electrically insulating materials, such as diamond, strontium titanate, yttrium-stabilized zirconium oxide, or sapphire.

[0028] Since the intermediate substrate is designed purely to fill the gaps between the sheets, it is composed of a different material than the sheets, which is advantageously cheaper and easier to obtain in large sizes (typically the same size as the carrier substrate).

[0029] Preferably, the material of the intermediate substrate is also selected to have behavior compatible with the behavior of the sheet during chemical mechanical polishing and / or during the use of the dummy donor substrate.

[0030] Therefore, for example, the material of the intermediate substrate advantageously has a hardness comparable to that of the sheet material, so that no offset occurs between the free surface of the sheet and the free surface of the intermediate substrate during polishing.

[0031] Furthermore, the material of the intermediate substrate advantageously has a thermal expansion coefficient close to that of the sheet, so that no deformation of the carrier substrate occurs during the heat treatment of the dummy donor substrate.

[0032] In some implementations, the intermediate substrate may include silicon or silicon oxide.

[0033] In other embodiments, the intermediate substrate may have a similar composition to the sheet but of lower quality. For example, the sheet may be composed of a single-crystal III-V material, and the intermediate substrate may be composed of a polycrystalline III-V material.

[0034] Figure 1 A top view and a cross-sectional view of a pseudo-donor substrate according to one embodiment of the present invention are shown.

[0035] The pseudo-donor substrate includes a carrier substrate 3, a sheet 1 and an intermediate substrate 2 arranged on the carrier substrate 3.

[0036] Pieces 1 are arranged at regular intervals, with a distance d1 between the nearest edges of two adjacent pieces. However, it should be noted that this arrangement of pieces is given only as an example; therefore, in some cases, pieces may have different shapes or be arranged at different distances from each other. Furthermore, the pieces are not necessarily arranged as shown... Figure 1 The illustrated square is not an example; the piece may have any other shape suitable for its intended use, with or without straight edges. For example, the piece may have a rectangular or circular shape, or any other shape composed of lines and / or curves.

[0037] The distance d1 is advantageously greater than or equal to 1 mm, preferably greater than or equal to 2 mm.

[0038] An intermediate substrate 2 is disposed on a carrier substrate 3 such that each piece 1 extends within a through opening 20 in the intermediate substrate 2. Therefore, the intermediate substrate forms a partition disposed between the pieces 1, such that the edges of each piece face the edges of the opening. Thus, a distance d2 exists between the edge of a piece and the nearest edge of the opening, which is in all cases less than a distance d1.

[0039] For example, the distance d2 is less than or equal to 250 µm, preferably less than or equal to 100 µm.

[0040] exist Figure 1In this embodiment, the wafer has four straight edges, and the opening in the intermediate substrate has four straight edges. The edges of each opening are arranged to face and be parallel to the corresponding edge of the wafer, so that there is a constant distance d2 between the wafer and the intermediate substrate. Therefore, at all points on the periphery of the wafer, the distance from the intermediate substrate is at most equal to d2. The remaining free space between the wafers is then sufficiently restricted to prevent the polishing pad from intruding between the wafers and eroding the edges of the wafers.

[0041] For example, piece 1 can have 12 mm 2 The dimensions are 3 mm and spaced apart by a distance d1 equal to 3 mm. The opening 20 then advantageously has a diameter of 15.75 mm. 2 The dimensions are such that the distance d2 between the edge of the sheet and the intermediate substrate is equal to 0.25 mm.

[0042] In order to form a pseudo-donor substrate, an intermediate substrate can be mounted on a carrier substrate before or after the wafer, as will be described below with reference to Figures 3 and 4.

[0043] Figure 2 Examples are shown from Figure 1 The intermediate substrate.

[0044] The intermediate substrate 2 is in the form of a flat plate with the same dimensions as the carrier substrate 3. For example, the diameters of the intermediate substrate and the carrier substrate are greater than or equal to 150 mm, preferably greater than or equal to 200 mm, and even more preferably greater than or equal to 300 mm.

[0045] The intermediate substrate 2 preferably has a thickness e2 (in a direction perpendicular to the plane of the substrate), which is substantially equal to the thickness e1 of the sheet (see [reference]). Figure 3B and Figure 4A This allows the free surface of the sheet to be flush with the free surface of the intermediate substrate after the sheet and intermediate substrate are mounted on the carrier substrate. In some cases, the thickness of the intermediate substrate can be slightly less than the thickness of the sheet, where flush fitting can be achieved by planarization or chemical mechanical polishing of the sheet after the sheet and intermediate substrate have been mounted on the carrier substrate. For example, the sheet can have a thickness of 5 µm to 10 µm greater than the thickness of the intermediate substrate.

[0046] Typically, the thickness of the sheet is on the order of 300 µm to 650 µm, depending on the thickness of the donor material. Therefore, the thickness of the intermediate substrate is on the order of 300 µm to 650 µm + / - 5 µm to 10 µm.

[0047] The intermediate substrate 2 has a plurality of openings 20 distributed in the proposed pattern for arranging sheets on the carrier substrate. In the illustrated example, the openings have the same shape and are regularly distributed in the form of lines and columns, but any other arrangement is conceivable. Preferably, the minimum distance between two openings is greater than or equal to 1000 µm so as not to weaken the intermediate substrate and allow for its processing.

[0048] Each opening is slightly larger than the size of the piece, allowing the piece to be placed within its corresponding opening. A distance d2 exists between the edge of the piece and the opening, small enough to prevent the polishing pad from intruding into the gap. Therefore, the width L20 of the opening can be defined as equal to d1 - L1 - 2xd2, where L1 is the width of the piece (see [reference]). Figure 4A ).

[0049] Intermediate substrates can be manufactured using various techniques.

[0050] According to a first embodiment, the intermediate substrate is formed of a plate, wherein openings are cut by means of laser, water jet, or any other method suitable for the material and size of the openings. Particularly advantageously, the plate is a silicon or silicon oxide plate.

[0051] According to a second embodiment, the intermediate substrate is formed by additive manufacturing. For example, working from a digital model of the intermediate substrate obtainable through computer-aided design, an additive manufacturing machine is controlled, in which powder is deposited on a carrier in the form of an elemental layer. A laser scans the surface of this layer to melt the powder except at the opening locations, and then a new powder elemental layer is deposited on the previously treated elemental layer. Once the desired thickness of the intermediate substrate is obtained, the substrate is removed from the carrier, and any unmelted powder is removed to release the opening. Particularly advantageously, the powder can be composed of the same material as the sheet, such as indium phosphide.

[0052] Other additive manufacturing methods (such as stereolithography or filament fusion) can be used to form intermediate substrates from other materials.

[0053] According to a third embodiment, the intermediate substrate can be produced by a semiconductor-on-insulator type structure. The structure comprises a substrate of silicon or another semiconductor material intended to form the intermediate substrate, a dielectric layer, and a stack of a processing substrate (e.g., a silicon substrate) serving as mechanical support. The intermediate substrate undergoes anisotropic etching, with the etching positioned at the opening to be formed, wherein the dielectric layer serves as an etch stop layer. The intermediate substrate can then be separated from the processing substrate, for example, by selective etching.

[0054] Of course, those skilled in the art can use any other suitable process depending on the size of the opening in order to form an intermediate substrate with appropriate mechanical strength.

[0055] As described above, the intermediate substrate precedes the wafer (see...). Figures 3A to 3C ) or after (see Figures 4A to 4C It is mounted on a carrier substrate.

[0056] Figure 3A The illustration schematically shows the intermediate substrate 2 being mounted on the carrier substrate 3 prior to the mounting of the wafers.

[0057] The intermediate substrate can be mounted by direct bonding to the carrier substrate or via an adhesive layer (not illustrated). This bonding is advantageously performed to allow subsequent removal of the intermediate substrate independently of the sheet.

[0058] To facilitate the alignment of the openings of the sheet and the intermediate substrate, it is advantageous to first mount the sheet on a temporary support and then transfer the sheet from the temporary support to a carrier substrate covered by the intermediate substrate.

[0059] Figure 3B An example is shown where piece 1 is placed on temporary support 4.

[0060] Temporary supports may be formed of, for example, one of the following materials: adhesive tape held by a frame, silicon substrate, glass substrate (non-limiting list).

[0061] The sheet can be cut from one or more corresponding donor substrates and placed on a temporary support by a robot (using a technique known as "pick-and-place"). Advantageously, the sheet has the same thickness as the corresponding donor substrate.

[0062] refer to Figure 3C The sheet 1 is bonded to the carrier substrate 3 via its free surface through an opening 20 in the intermediate substrate 2, and then the temporary support is removed to expose the opposing surfaces of the sheet. Advantageously, the sheet is directly bonded to the carrier substrate, but a bonding layer can be used between the sheet and the carrier substrate.

[0063] Alternatively, a robot can be used to mount the wafer directly onto the carrier substrate with sufficient precision using alignment marks set on the carrier substrate. This avoids the use of temporary supports and the transfer of the wafer from temporary supports to the carrier.

[0064] refer to Figure 3D Chemical mechanical polishing is performed on the free surfaces of sheet 1 and intermediate substrate 2. As shown, due to the small distance between the edges of the openings of the sheet and the intermediate substrate, the polishing pad 5 operates essentially in the plane of the free surface of the sheet without intruding between the sheets. Therefore, the edges of the sheet remain straight (not rounded).

[0065] In some cases, the chemical mechanical polishing can precede the planarization of the sheets by mechanical abrasion (grinding). This planarization can be advantageous, particularly when the sheets have different thicknesses, so that their free surfaces are substantially in the same plane, or to reduce the thickness of the sheets, for example if this is greater than the thickness of the intermediate substrate. However, if the sheets have coplanar free surfaces, this planarization can be omitted and chemical mechanical polishing can be performed directly.

[0066] Optionally, prior to chemical mechanical polishing, a resin or polymer layer (not shown) may be applied between the sheet and the intermediate substrate to fill the space between the sheet and the intermediate substrate.

[0067] Typically, the coefficient of thermal expansion of this resin or polymer differs significantly from that of the sheets and the carrier substrate. Therefore, using this material alone to fill the gaps between the sheets (without an intermediate substrate) will result in significant deformation of the assembly during heat treatment. However, with an intermediate substrate, the amount of resin or polymer used can be minimized, thus reducing the risk of assembly deformation.

[0068] Figures 4A to 4E A variation of the method for manufacturing a dummy donor substrate is illustrated schematically, wherein a piece is mounted on a carrier substrate prior to mounting an intermediate substrate.

[0069] To facilitate the alignment of the openings of the sheet and the intermediate substrate, it is advantageous to first mount the sheet on a temporary support and then transfer the sheet from the temporary support to the carrier substrate.

[0070] Figure 4A An example is shown where piece 1 is placed on temporary support 4.

[0071] Temporary supports may be formed of, for example, one of the following materials: adhesive tape held by a frame, silicon substrate, glass substrate (non-limiting list).

[0072] The sheet can be cut from one or more corresponding donor substrates and placed on a temporary support by a robot (using a technique known as "pick-and-place"). Advantageously, the sheet has the same thickness as the corresponding donor substrate.

[0073] refer to Figure 4B Piece 1 is bonded to carrier substrate 3 via its free surface, and then the temporary support is removed to expose the opposing surfaces of the piece (see [reference]). Figure 4C Advantageously, the wafer is directly bonded to the carrier substrate, but a bonding layer can be used between the wafer and the carrier substrate.

[0074] Alternatively, using a robot, alignment marks set on the carrier substrate can be used to mount the wafer directly onto the carrier substrate with sufficient precision. This avoids the use of temporary supports and the need to transfer the wafer from temporary supports to the carrier.

[0075] refer to Figure 4D The intermediate substrate 2 is mounted on the carrier substrate 3 such that each opening 20 surrounds the corresponding piece 1.

[0076] The intermediate substrate can be mounted by direct bonding to the carrier substrate or via an adhesive layer (not illustrated). This bonding is advantageously performed to allow subsequent removal of the intermediate substrate independently of the sheet.

[0077] refer to Figure 4E Chemical mechanical polishing is performed on the free surfaces of sheet 1 and intermediate substrate 2. As shown, due to the small distance between the edges of the openings of the sheet and the intermediate substrate, the polishing pad 5 operates essentially in the plane of the free surface of the sheet without intruding between the sheets. Therefore, the edges of the sheet remain straight (not rounded).

[0078] In some cases, the chemical mechanical polishing can precede the planarization of the sheets by mechanical abrasion (grinding). This planarization can be advantageous, particularly when the sheets have different thicknesses, so that their free surfaces are substantially in the same plane, or to reduce the thickness of the sheets, for example if this is greater than the thickness of the intermediate substrate. However, if the sheets have coplanar free surfaces, this planarization can be omitted and chemical mechanical polishing can be performed directly.

[0079] Optionally, prior to chemical mechanical polishing, a resin or polymer layer (not shown) may be applied between the sheet and the intermediate substrate to fill the space between the sheet and the intermediate substrate.

[0080] Typically, the coefficient of thermal expansion of this resin or polymer differs significantly from that of the sheets and the carrier substrate. Therefore, using this material alone to fill the gaps between the sheets (without an intermediate substrate) will result in significant deformation of the assembly during heat treatment. However, due to the intermediate substrate, the amount of resin or polymer used can be minimized, thus reducing the risk of assembly deformation.

[0081] A particular advantage is in the execution Figure 3D and Figure 4EFollowing the chemical mechanical polishing illustrated herein, the intermediate substrate is removed from the carrier substrate. Depending on the materials involved and the method of attaching the intermediate substrate to the carrier substrate, various techniques can be used to perform this removal. For example, if the intermediate substrate is bonded to the carrier substrate via an adhesive layer, removal may include a heating assembly to liquefy the adhesive layer, followed by applying a tensile force perpendicular to the main surface of the carrier substrate and in the removal direction of the carrier substrate, or a combination thereof. Alternatively, the adhesive layer may be destroyed or at least degraded by applying a suitable solvent.

[0082] refer to Figure 5 A weakening region 10 is formed in the wafer 1, and a chip 11 is defined on the surface of each wafer. The weakening region is advantageously obtained by implanting ion seed particles (e.g., hydrogen and / or helium) indicated by arrows into the wafer.

[0083] The weakened region is preferably formed after chemical mechanical polishing, but may optionally be formed before that. In particular, when the sheet is placed on the carrier substrate before the intermediate substrate, the weakened region may be formed in the sheet before the intermediate substrate is positioned on the carrier substrate to surround the sheet.

[0084] In some cases, if the intermediate substrate is formed of a material resistant to implantation (e.g., silicon oxide), implantation can be performed while the intermediate substrate is in place on the carrier substrate.

[0085] This provides a dummy donor substrate 100, which can then be bonded to a acceptor substrate to transfer the chip to the acceptor substrate. The acceptor substrate is typically a semiconductor substrate, such as a silicon substrate.

[0086] refer to Figure 6 The free surface of the sheet is bonded to the acceptor substrate 6. Advantageously, the sheet is directly bonded to the acceptor substrate, but a bonding layer may be used between the sheet and the acceptor substrate.

[0087] refer to Figure 7 Using Smart Cut TM The process separates the wafer 1 along the weakened region 10 in order to transfer the chip 11 to the acceptor substrate 6. Separation can be initiated by heat treatment, mechanical and / or chemical action at the weakened region.

[0088] The chips transferred to the acceptor substrate are thus spaced apart by a distance d1, but have non-circular edges, making them functional across their entire surface.

Claims

1. A method for manufacturing a substrate (100), the substrate (100) being referred to as a pseudo-donor substrate, the substrate comprising a plurality of sheets (1) arranged spaced apart from each other on a carrier substrate (3), the method comprising the steps of: - The sheet (1) and intermediate substrate (2) are placed on the carrier substrate (3), the intermediate substrate (2) being made of a different material than the sheet, or the intermediate substrate (2) having a similar composition to the sheet but of lower quality, the intermediate substrate including a plurality of through openings (20) such that each sheet (1) extends in a corresponding through opening (20) of the intermediate substrate, and - The sheet (1) disposed in the opening of the intermediate substrate is chemically and mechanically polished by a polishing pad, the sheet and the intermediate substrate being separated by a space gap of less than or equal to 250 μm to minimize the intrusion of the polishing pad between the sheet and the intermediate substrate.

2. The method according to claim 1, wherein, The distance (d1) between two adjacent pieces (1) is greater than or equal to 1 mm, preferably greater than or equal to 2 mm.

3. The method according to claim 1 or 2, wherein, The distance (d2) between each piece (1) and the edge of the corresponding through opening (20) is less than or equal to 250 μm, preferably less than or equal to 100 μm.

4. The method according to any one of claims 1 to 3, wherein, The wafer comprises semiconductor materials, such as III-V group materials.

5. The method according to any one of claims 1 to 4, wherein, The intermediate substrate (2) is formed by cutting an opening (20) through a silicon or silicon oxide substrate, particularly by cutting an opening (20) through a silicon or silicon oxide substrate by means of a laser or water jet.

6. The method according to any one of claims 1 to 4, wherein, The intermediate substrate (2) is formed by additive manufacturing process.

7. The method according to any one of claims 1 to 4, wherein, The intermediate substrate (2) is formed from a semiconductor substrate bonded to the processing substrate via a dielectric layer, and the opening is formed by selectively etching the semiconductor material down to the dielectric layer.

8. The method according to any one of claims 1 to 7, wherein, The thickness (e2) of the intermediate substrate (2) is less than or equal to the thickness (e1) of the piece (1).

9. The method according to any one of claims 1 to 8, the method comprising removing the intermediate substrate (2) after performing the chemical mechanical polishing.

10. The method according to any one of claims 1 to 9, the method comprising forming a weakening region (10) in the wafer to define a corresponding chip (11) in each wafer.

11. The method according to any one of claims 1 to 10, wherein, The piece (1) is placed on the carrier substrate (3) before the intermediate substrate (2).

12. The method according to any one of claims 1 to 10, wherein, The intermediate substrate (2) is placed on the carrier substrate (3) before the sheet (1).

13. A method for transferring a chip (11) to a recipient substrate (6), the method comprising the steps of: - A pseudo-donor substrate (100) is formed using the method according to claim 10. - The pseudo-donor substrate (100) is bonded to the acceptor substrate (6) via the sheet (1), and - Separate the individual pieces (1) along the weakened region (10) to transfer the individual chips (11) to the acceptor substrate (6).

Images