METHOD FOR MANUFACTURING A STRUCTURE COMPRISING AT LEAST TWO CHIPS ON A SUBSTRATE

Abstract

The invention relates to a method for manufacturing a structure comprising at least two chips (p11, p12, p13, p14) on a receiving substrate (3), comprising: - the formation of a pseudo-donor substrate (10) by placing at least one block (P1, P2, P3) of at least one donor substrate (2) on a support substrate (1); - the bonding of said pseudo-donor substrate (10) to a receiving substrate (3) via the blocks so that each block covers at least partially at least two distinct areas of interest (Z1, Z2, Zn) of the receiving substrate (3); - the transfer of a portion (P'1, P'2, P'3) of said blocks (P1, P2, P3) onto the receiving substrate (3); - at least one mechano-chemical polishing step of the paving stones (P1, P2, P3) of the pseudo-donor substrate and / or portions of paving stones transferred onto the receiving substrate;- after said at least one mechano-chemical polishing step, a removal of material from said portions (P'1, P'2, P'3) of paving stones so as to divide each portion of paving stone into at least two chips (p11, p12, p13, p14) each arranged on a respective zone of interest (Z1, Z2, Zn). Figure for the abbreviation: Fig 6;

Description

Title of the invention: METHOD FOR MANUFACTURING A STRUCTURE COMPRISING AT LEAST TWO CHIPS ON A SUBSTRATE Technical field

[0001] The invention relates to a method of manufacturing a structure comprising at least two chips on a substrate. STATE OF THE ART

[0002] In the field of microelectronics, optics or optoelectronics, the design of multilayer structures sometimes requires transferring tiles in the form of portions of a layer from a donor substrate to a receiving substrate.

[0003] This type of process is generally referred to as a paving process, and involves a partial transfer of a layer taken from the donor substrate to form one or more tiles arranged in a pattern or at a predetermined location on the recipient substrate.

[0004] Such tiling may be made necessary by a difference in size between the donor substrate and the recipient substrate. Indeed, due to this difference in size, it is not possible to transfer an entire layer of the donor substrate onto the recipient substrate.

[0005] A well-known layer transfer method is the Smart Cut™ method, in which a weakening zone delimiting the layer to be transferred is formed by implantation of atomic species in the donor substrate, the donor substrate is bonded to the receiving substrate, and the donor substrate is detached along the weakening zone to transfer the layer from the donor substrate to the receiving substrate. However, this method assumes that the donor substrate and the receiving substrate have the same size.

[0006] However, while silicon substrates are available with a relatively large size, typically a diameter of 300 mm, other materials of interest currently only exist in the form of bulk substrates of smaller size, for example 10 or 15 cm in diameter. Furthermore, these materials of interest are sometimes particularly expensive, so that it is desirable to minimize any waste formed during the transfer. This is the case in particular for III-V semiconductor materials, including nitrides (for example, for binary compounds, indium nitride (InN), gallium nitride (GaN) and aluminum nitride (AIN)), arsenides (for example, for binary compounds, indium arsenide (InAs), gallium arsenide (GaAs) and aluminum arsenide (AlAs)), and phosphides (e.g., for binary compounds, indium phosphide (InP), gallium phosphide (GaP) and aluminum phosphide (A1P)).

[0007] Instead of transferring an entire layer of the donor substrate, a solution based on the Smart Cut™ process consists of forming an intermediate substrate called a pseudodonor, by removing one or more blocks from at least one donor substrate and transferring said blocks onto a support substrate having a diameter identical to that of the receiving substrate. The method then comprises forming, by implantation of atomic species, a weakening zone in each block, bonding the pseudodonor substrate to the receiving substrate via the blocks, and detaching each block along the weakening zone so as to transfer a portion of each block onto the receiving substrate.

[0008] During the process, it is generally necessary to polish the paving stones, after the formation of the pseudo-donor substrate and / or after the transfer of the paving stone portions onto the receiving substrate. Such polishing, which is typically of the chemical-mechanical type (CMP, acronym for the English term “Chemical Mechanical Polishing”) aims to planarize the free surface of the paving stones or paving stone portions.

[0009] A particular difficulty arises when the paving is not very dense, that is to say that the coverage rate of the paving stones on the receiving substrate, which corresponds to the ratio between the total surface area of ​​the paving stones and the total surface area of ​​the receiving substrate, is typically less than 50%, or even less than 30%. In this situation, there is a significant distance, typically of the order of a few millimeters, between the paving stones on the pseudo-donor substrate and on the receiving substrate.

[0010] However, the polishing fabric which is applied against the paving stones is likely to deform at the level of the hollows formed by the spaces between the paving stones. This deformation induces differences in polishing height between paving stones and an overconsumption of material on the edges of the paving stones compared to their center.

[0011] These inhomogeneities generated by polishing penalize the subsequent use of the blocks to form electronic, optical or optoelectronic components. BRIEF DESCRIPTION OF THE INVENTION

[0012] An aim of the invention is to design a method for manufacturing a structure comprising at least two chips on a support substrate, which makes it possible to remedy the aforementioned polishing defects.

[0013] To this end, the invention proposes a method for manufacturing a structure comprising at least two chips on a receiving substrate, comprising:

[0014] - the formation of a pseudo-donor substrate by placing at least one block of at least less than one donor substrate on a support substrate;

[0015] - bonding said pseudo-donor substrate to a recipient substrate via paving stones so that each paving stone at least partially covers at least two distinct areas of interest of the recipient substrate;

[0016] - transferring a portion of said blocks onto the receiving substrate;

[0017] - at least one step of chemical-mechanical polishing of the paving stones of the pseudo-substrate donor and / or portions of paving stones transferred to the recipient substrate;

[0018] - after said at least one chemical-mechanical polishing step, a removal of material of said portions of paving stones so as to divide each portion of paving stone into at least two chips each arranged on a respective area of ​​interest.

[0019] Resizing the tile portions after their transfer to the receiving substrate to form the chips makes it possible to increase the density of the tiles on the pseudo-donor substrate and to reduce the distances between tiles and, after transfer, between tile portions. As a result, polishing defects linked to excessively large distances between the tiles or between the transferred tile portions are minimized.

[0020] After the etching step, the coverage rate of the chips on the receiving substrate, i.e. the ratio between the total surface area of ​​the chips and the total surface area of ​​the receiving substrate, is advantageously less than 50%, preferably less than 30%.

[0021] Particularly advantageously, the coverage rate of the paving stones on the pseudo-donor substrate, i.e. the ratio between the total surface area of ​​the paving stones and the total surface area of ​​the support substrate, is greater than 50%, preferably greater than 75%.

[0022] Each block may have a side with a length greater than or equal to 5 mm, preferably greater than or equal to 8 mm, and preferably greater than or equal to 10 mm.

[0023] Furthermore, each chip may have a side with a length less than or equal to 5 mm, preferably less than or equal to 3 mm, and more preferably less than or equal to 1 mm.

[0024] Particularly advantageously, the distance between two adjacent blocks is less than or equal to 3 mm, preferably less than or equal to 1 mm.

[0025] The distance between two adjacent chips may, however, be greater than or equal to 3 mm, preferably greater than or equal to 5 mm.

[0026] In certain embodiments, each tile at least partially covers two distinct areas of interest of the receiving substrate and a chip is formed from said tile on each respective area of ​​interest.

[0027] In other embodiments, each tile covers a respective corner of four distinct areas of interest of the receiving substrate arranged in a square or rectangle, and a chip is formed from said tile on each corner of the respective area of ​​interest.

[0028] In other embodiments, each tile is in the form of a strip at least partially covering at least three aligned areas of interest of the receiving substrate and a chip is formed from said tile on each respective area of ​​interest.

[0029] In a particularly advantageous manner, the support substrate and the receiving substrate have a substantially identical diameter, greater than the diameter of the donor substrate.

[0030] The bonding of the pseudo-donor substrate to the recipient substrate can be carried out by molecular adhesion.

[0031] In a preferred embodiment, the transfer of each portion of tile successively comprises the formation of a weakening zone by implantation of atomic species in each tile of the pseudo-donor substrate to define a portion of tile to be transferred, the bonding of the pseudo-donor substrate to the receiving substrate via the tiles, and the detachment of each tile along the weakening zone.

[0032] In other embodiments, the transfer of each tile portion comprises thinning by grinding and / or etching each tile of the pseudodonor substrate.

[0033] Each block may have a thickness of between 20 μm and 1000 μm, preferably between 100 μm and 700 μm, and the transferred portion of each block may have a thickness of between 30 nm and 1.5 μm.

[0034] Each block may include:

[0035] - a semiconductor material, such as a III-V material, in particular nitride indium nitride (InN), gallium nitride (GaN), aluminum nitride (AIN), indium arsenide (InAs), gallium arsenide (GaAs), aluminum arsenide (AlAs), indium phosphide (InP), gallium phosphide (GaP) or aluminum phosphide (AlP), or a material IV or IV-IV, including germanium or silicon carbide (SiC),

[0036] - a piezoelectric material, such as lithium tantalate (LiTaO3), lithium niobate (LiO3), lithium (LiNbO3), potassium sodium niobate (KxNahxNbO3 or KNN), barium titanate (BaTiO3), quartz, lead zirconate titanate (PZT), a compound of lead magnesium niobate and lead titanate (PMN-PT), zinc oxide (ZnO), aluminum nitride (AIN) or aluminum scandium nitride (AIScN), and / or

[0037] - an electrically insulating material, such as diamond, strontium titanate, yttria zirconia or sapphire.

[0038] In some embodiments, the method comprises a step of forming by epitaxy at least one epitaxial layer on each portion of tile, the removal of material to divide each portion of tile into chips being carried out after said epitaxy step.

[0039] In some embodiments, the material removal comprises:

[0040] - the formation of a mask comprising a protective film partially covering said paving portions in a pattern defining said chips in each paving portion and at least one opening defining a space to be formed between two chips;

[0041] - the engraving of each portion of block through each opening of the mask of so as to form said space to separate said chips from each other.

[0042] The etching can be carried out using an etching solution and the mask is formed from a photosensitive resin.

[0043] Alternatively, the etching can be carried out using an ion beam and the mask is formed from a metal.

[0044] In other embodiments, the material removal is performed selectively by a focused beam of ions, said beam being controlled to scan only the regions of the paving stone portions to be removed. BRIEF DESCRIPTION OF THE FIGURES

[0045] Other characteristics and advantages of the invention will emerge from the detailed description which follows, with reference to the appended drawings, in which:

[0046] - [Fig.l] is a top view of the receiving substrate on which the areas of interest are schematized,

[0047] - [Fig.2] illustrates a step of taking tiles from a donor substrate,

[0048] - [Fig.3] illustrates a step of placing said paving stones on a support substrate for form a pseudo-donor substrate,

[0049] - [Fig.4] illustrates a stage of formation of a weakening zone in said cobblestones,

[0050] - [Fig.5] illustrates a step of bonding the pseudo-donor substrate to a substrate receiver through the paving stones,

[0051] - [Fig.6] illustrates a step of transferring the portions of paving stones onto the second substrate support following the detachment of the paving stones along the weakened zone,

[0052] - [Fig.7] illustrates a step of forming a mask on the portions of paving stones of so as to delimit the chips to be formed,

[0053] - [Fig.8] illustrates a step of engraving the areas of the paving stones not protected by the mask to form the chips,

[0054] - [Fig.9] illustrates a step of removing the protective film after etching,

[0055] - [Fig.10A] illustrates an embodiment in which each block covers in part two adjacent areas of interest, and [Fig.lOB] illustrates an example of the distribution of chips formed from said tiles,

[0056] - [Fig.l 1 A] illustrates an embodiment in which each paving stone covers in part several aligned areas of interest, and [Fig.l IB] illustrates an example of distribution of the chips formed from said tiles,

[0057] - [Fig.l2A] illustrates an embodiment in which each paving stone covers in part four areas of interest arranged in a square, and [Fig.l2B] illustrates an example of the distribution of chips formed from said tiles.

[0058] For reasons of readability, the drawings are not necessarily drawn to scale. Furthermore, the number and shape of the areas of interest, blocks and chips shown schematically in the drawings is given for illustration purposes only. DETAILED DESCRIPTION OF EMBODIMENTS

[0059] The invention proposes to form a structure comprising at least two chips on a receiving substrate, in which polishing inhomogeneities are avoided even in the case where the chips are spaced apart by a relatively large distance, and / or distributed in a sparse manner on the receiving substrate, by using a so-called pseudo-donor substrate comprising tiles intended to each form at least two chips, said chips being distributed over at least two distinct areas of interest of the receiving substrate. The pseudo-donor substrate is bonded to the receiving substrate via the tiles, so as to transfer a portion of the tiles to the receiving substrate. Then, a removal of material on each tile, in particular between the chips, makes it possible to form each chip.

[0060] By sparsely dense, it is meant in the present text that the coverage rate of the chips on the receiving substrate, which corresponds to the ratio between the total surface area of ​​the chips and the total surface area of ​​the receiving substrate, is typically less than 50%, or even less than 30%, and / or that the distance between two adjacent chips is greater than or equal to 3 mm, or even greater than or equal to 5 mm.

[0061] By area of ​​interest is meant in the present text an area of ​​the receiving substrate intended to subsequently form an electronic circuit distinct from the electronic circuit formed in an adjacent area. In particular, in a subsequent step of manufacturing said electronic circuits, the receiving substrate can be cut to form individual chips.

[0062] The areas of interest are not necessarily visible on the receiving substrate; in particular, they may be defined on a plane indicating the location of each component on the receiving substrate at each stage of the manufacturing process. The location of the areas of interest on the receiving substrate is related to said plane using a reference frame of the receiving substrate, i.e., a coordinate system attached to the receiving substrate, which makes it possible to define the position of each point on the surface of the receiving substrate. For example, said reference frame may comprise a point of origin identifiable on an edge of the receiving substrate, such as a notch conventionally used in the semiconductor industry, and two orthogonal axes extending in the plane of the substrate, one of the axes extending diametrically from the notch and the other axis intersecting the first axis at the center of the substrate.

[0063] [Fig.l] illustrates an example of distribution of the areas of interest on a receiving substrate. The receiving substrate 3 has a plurality of areas of interest Zl, Z2, Zn (n being an integer between 1 and the total number of areas of interest) delimited by dotted lines. These areas are not necessarily materialized on the surface of the receiving substrate but the location of each area of ​​interest in a reference frame of the receiving substrate is known.

[0064] In the example illustrated in [Fig.l], the areas of interest all have an identical rectangular shape and are arranged on the receiving substrate in rows and columns to form a grid. However, in other embodiments not illustrated, the areas of interest may have different dimensions and / or shapes.

[0065] The transfer method involves at least one chemical-mechanical polishing of the tiles. Such polishing can be carried out after the tiles have been placed on the support substrate to form the pseudo-donor substrate, before bonding to the receiving substrate, on the portions of tiles transferred to the receiving substrate, or even both on the tiles of the pseudo-donor substrate and on the portions of tiles transferred to the receiving substrate.

[0066] The fact that the tiles are sized to form at least two chips makes it possible to increase the coverage rate of the tiles and / or to reduce the distance between tiles on the pseudo-donor substrate relative respectively to the coverage rate of the chips on the recipient substrate, and the distance between chips.

[0067] Thus, the coverage rate of the paving stones on the pseudo-donor substrate, i.e. the ratio between the total surface area of ​​the paving stones and the total surface area of ​​the support substrate, is advantageously greater than 50%, preferably greater than 75%. The receiving substrate may have a diameter substantially identical to that of the support substrate. In this case, this coverage rate will also be that of the portions of paving stones transferred to the receiving substrate.

[0068] Advantageously, the distance between two adjacent blocks is less than or equal to 3 mm, preferably less than or equal to 1 mm.

[0069] Furthermore, the pseudo-donor and recipient substrates may have the shape of a fairly thin disc typically a few hundred μm thick (commonly called a "slice" in the field of microelectronics) or a rectangular shape or any geometric shape.

[0070] Consequently, the paving stones (and the transferred paving stone portions) are advantageously distributed sufficiently densely so that the chemical-mechanical polishing does not produce thickness inhomogeneities between paving stones or transferred paving stone portions. Indeed, the deformation of the polishing fabric between adjacent paving stones is minimized, so that the polishing is substantially uniform over the entire surface of the paving stones or paving stone portions.

[0071] Only after this polishing step are the chips formed by removal of material from the portions of the tiles transferred to the receiving substrate. This removal of material leads to a reduction in the density of the chips compared to that of the tiles but, since no chemical-mechanical polishing step of the chips must be carried out, it does not induce any risk of loss of homogeneity of the thickness and shape of the chips.

[0072] The removal of material can be carried out by different techniques, which are known in themselves.

[0073] Some techniques use a mask to protect the surface of the chips and expose the surface of the tile portions intended to be removed by applying an etchant.

[0074] Particularly advantageously, the mask is formed by photolithography, the protective film then being formed from a photosensitive resin resistant to the etching agent which is a chemical etching composition. Photolithography being very precise, it therefore makes it possible to guarantee that the chips have the desired shape and position.

[0075] Alternatively, the etching agent is an ion beam (a technique known as "sputtering"). The mask may comprise a metallic protective film or a photosensitive resin, which protects the material of the ion beam tiles in the areas covered by the protective film.

[0076] The mask is removed after the paving portions have been engraved over all or part of their thickness.

[0077] It will be noted that it is possible to avoid the use of a mask if a selective etching process is used using a focused beam of controlled etching ions to scan only the areas of the portions of paving stones to be eliminated.

[0078] The pseudo-donor substrate can be produced by placing the tiles one by one, or in small groups of tiles, on the support substrate, for example by the “Pick and Place” method; on the other hand, the transfer of the tiles from the pseudo-donor substrate to the receiving substrate can be carried out simultaneously.

[0079] The method therefore makes it possible to subdivide a block into several smaller chips, extending over several distinct, preferably adjacent, areas of interest. The method thus has the advantage of forming chips of very small dimensions without having to place them individually on the receiving substrate, and by overcoming the problems of inhomogeneities due to chemical-mechanical polishing if the chips are not very densely distributed.

[0080] For example, each block initially has a side with a length greater than or equal to 5 mm, preferably greater than or equal to 8 mm, and preferably greater than or equal to 10 mm.

[0081] Advantageously, the paving stones are made of a material which is not commercially available. commercially in the form of a large donor substrate. Thus, the donor substrate may have a diameter of less than 30 cm, for example of the order of 10 or 15 cm.

[0082] This is the case in particular for III-V semiconductor materials, including nitrides (for example, as regards binary compounds, indium nitride (InN), gallium nitride (GaN) and aluminum nitride (AIN)), arsenides (for example, as regards binary compounds, indium arsenide (InAs), gallium arsenide (GaAs) and aluminum arsenide (AlAs)), and phosphides (for example, as regards binary compounds, indium phosphide (InP), gallium phosphide (GaP) and aluminum phosphide (AlP)).

[0083] This is also the case for IV or IV-IV semiconductor compounds, such as germanium and silicon carbide.

[0084] The blocks may also be made of a piezoelectric material, for example lithium tantalate (LiTaO3) or lithium niobate (LiNbO3), potassium sodium niobate (KxNai_xNbO3 or KNN), barium titanate (BaTiO3), quartz, lead zirconate titano (PZT), a compound of lead magnesium niobate and lead titanate (PMN-PT), zinc oxide (ZnO), aluminum nitride (AIN) or aluminum scandium nitride (AIScN) (non-limiting list).

[0085] The blocks can also be made of an electrically insulating material, such as, for example, diamond, strontium titanate (SrTiO3), yttria zirconia (YSZ), or sapphire.

[0086] Figures 2 to 9 schematically illustrate the formation of a pseudo-donor substrate comprising the tiles placed on a first support substrate and the transfer of the tile portions onto a receiving substrate, then the division of each tile portion into at least two chips.

[0087] With reference to [Fig. 2], blocks P1-P3 are cut from a donor substrate 2. The cutting of the blocks can be carried out by any technique known to those skilled in the art. It can in particular be carried out by sawing and / or cleaving, or by laser cutting. It can also, for example, be combined with a step of partial plasma etching of the cutting lines, a technique known by the English term “plasma dicing”.

[0088] [Fig.3] illustrates the placement of the tiles taken from the donor substrate of [Fig.2] on a support substrate 1 to form a pseudo-donor substrate 10.

[0089] Placement may be implemented by the “Pick and Place” technique, whereby a robot picks up a tile, or group of tiles, previously cut from the donor substrate and places it at a predetermined location on the support substrate.

[0090] In certain embodiments, each paving stone adheres to the support substrate by molecular adhesion. For this purpose, surface treatments of the paving stones and / or the The support substrate can be implemented beforehand to promote good molecular adhesion. These treatments may include cleaning, the deposition of a bonding layer such as silicon oxide (SiO2), plasma activation before bonding and annealing.

[0091] In other embodiments (not shown), the bonding of the paving stones to the support substrate may involve an intermediate bonding layer, for example a polymer bonding layer, a eutectic bonding layer or a ceramic adhesive layer.

[0092] The support substrate 1 advantageously has a diameter or dimensions greater than those of the donor substrate 2. For example, the support substrate 1 may have the shape of a disc having a diameter of the order of 300 mm.

[0093] [Fig. 4] illustrates the formation of a weakening zone in said blocks P1-P3 in order to delimit a surface portion of said blocks intended to be transferred onto a receiving substrate. As shown diagrammatically by the arrows, the weakening zone 11 is advantageously formed by implantation of atomic species, such as hydrogen and / or helium, in the blocks, at a depth corresponding to the thickness of the layer to be transferred.

[0094] Optionally, the pseudo-donor substrate can be subjected to chemical-mechanical polishing of the surface of the paving stones.

[0095] [Fig.5] illustrates the bonding of the pseudo-donor substrate of [Fig.3] onto a recipient substrate via the blocks.

[0096] During this bonding, the two substrates are positioned relative to each other in such a way that each tile of the pseudo-donor substrate 10 at least partially covers at least two distinct areas of interest of the recipient substrate 3.

[0097] In the illustrated example, each tile partially covers four areas of interest arranged in a square or rectangle, that is to say that the four areas of interest belong to two adjacent rows and two columns, the centers of the four areas of interest forming the four vertices of a square or a rectangle. Each tile therefore covers not only a part of the surface of said areas of interest but also the surface of the receiving substrate located between the areas of interest, which has, in this example, a cross shape. In general, in order to optimize the surface of the receiving substrate and minimize material losses, the distance between areas of interest is minimized. The surface of each area of ​​interest covered by the tile is adapted according to the size of the components to be formed in or on the chip or the area of ​​interest.

[0098] In a particularly advantageous manner, each paving stone adheres to the receiving substrate 3 by molecular adhesion. For this purpose, surface treatments of the paving stones and / or the receiving substrate may be implemented beforehand in order to promote good molecular adhesion. These treatments may include in particular cleaning, the deposition of a bonding layer such as silicon oxide (SiO2), plasma activation before bonding, polishing and annealing, preferably at low temperature (i.e. typically below 300°C).

[0099] The support substrate 1 and the receiving substrate 3 advantageously have a substantially identical diameter, for example of the order of 300 mm.

[0100] Then, with reference to [Fig.6], the blocks are detached along the weakening zone 11, in order to transfer the portions P' 1, P'2, P'3 delimited by said weakening zone onto the receiving substrate.

[0101] The tiles placed on the support substrate typically have a thickness of between 20 μm and 1000 μm, preferably between 100 μm and 700 μm. The transferred portion of each tile generally has a thickness of between 30 nm and 1.5 μm.

[0102] According to an alternative to the Smart Cut™ process which has just been described, the portions of paving stones can be obtained by thinning by grinding and / or etching each paving stone of the pseudo-donor substrate after bonding the pseudo-donor substrate to the receiving substrate. However, an advantage of the Smart Cut™ process is to minimize the loss of material, the pseudo-donor substrate possibly being recycled and used to transfer portions of paving stones again onto the same receiving substrate or onto another receiving substrate.

[0103] Optionally, after transferring said portions of paving stones onto the receiving substrate, chemical-mechanical polishing of the surface of the portions of paving stones can be carried out.

[0104] [Fig.7] illustrates the formation, for example by photolithography, of a mask comprising a protective film M11, M12, M13, M14 partially covering each portion of the block and openings extending between the portions of protective film.

[0105] The protective film is configured to define a pattern corresponding to the geometry and location of each chip on each respective area of ​​interest.

[0106] The openings typically correspond to the surface of the receiving substrate located between the areas of interest. Thus, in the illustrated example, the openings are cross-shaped and delimit four rectangular portions M1 1-M14 of the protective film on each portion of the pad.

[0107] According to one embodiment, the protective film does not extend to the edges of the block portion located in the area of ​​interest. This makes it possible, in the following etching step, to also remove a peripheral region of the block portions, for example to resize said portion. However, in order to minimize the loss of material, the blocks are preferably sized to minimize the peripheral region to be removed.

[0108] The film may be made of any suitable resin. In particular in the field microelectronics, such photosensitive resins, marketed for example by the companies Shipley or AZ Electronic Materials, are dispensed in a viscous state and spread on the substrates using spin coatings (a spin coating operation according to English terminology) then annealed. A UV exposure step, after development, allows the exposed areas to be kept or, on the contrary, removed. According to a variant known under the English name of "dry film photo resist", the application of these resins can also be done by laminating a thick film, typically with a thickness between 15 and 50 μm, supplied in the form of rolls.

[0109] With reference to [Fig.8], an etching solution is applied to the structure of [Fig.7]. The composition of the etching solution is chosen according to the material of the blocks. For example, in the case where the blocks are made of InP, wet etching may be used in a bath of hydrochloric acid (HCl) and phosphoric acid (H3PO4). Plasma etching based on halogenated gases (based on chlorine for example or methane / dihydrogen mixtures (CH4 / H2) may also be used.

[0110] Advantageously, the etching solution does not attack or only slightly attacks the material of the receiving substrate 3.

[0111] Alternatively, sputtering under an ion beam, argon for example, can also be used. In this case, the protective film is advantageously metallic.

[0112] At the end of the etching, the part of the blocks not covered by the protective film was removed, over all or part of the thickness of the blocks, to separate the chips.

[0113] With reference to [Fig.9], the protective film is removed so as to free the surface of the chips. The structure is thus ready for subsequent manufacturing steps, for example deposition or epitaxy of one or more additional layers on the chips, formation of electronic components in or on the chips, cutting of the receiving substrate to separate the chips, etc.

[0114] It will be noted that, after the formation of the chips, no chemical-mechanical polishing is implemented in order not to create inhomogeneity within the chips. In other words, any chemical-mechanical polishing step is carried out either on the pseudo-donor substrate or on the receiving substrate after the transfer of the tile portions, but before the removal of material leading to the production of the chips. Thus, the chemical-mechanical polishing is carried out in all cases on the tiles or tile portions, which have relatively large dimensions, greater than the dimension necessary for the production of the targeted chips. More precisely, each tile has a dimension greater than a multiple of the dimension of the chips targeted in the manufacturing process. For example, each tile may have a dimension two or four times greater than the targeted dimension.

[0115] Multiple geometries can be obtained depending on the destination of the structure. final and the arrangement of the areas of interest.

[0116] In certain embodiments, each tile at least partially covers two distinct areas of interest of the receiving substrate and a chip is formed from said tile on each respective area of ​​interest.

[0117] For example, as illustrated in [Fig. 10A], each transferred tile and tile portion P' 1 may be arranged so as to cover a portion of two adjacent areas of interest as well as the surface of the receiving substrate between said areas of interest. The removal of material may be carried out so as to remove the material from each tile portion facing the surface separating the areas of interest, and, where appropriate, the material from each tile portion facing each area of ​​interest to respect the desired geometry for each chip pl 1, pl 2 (see [Fig. 10B]).

[0118] According to another example, illustrated in [Fig. 1 1A], each tile and transferred tile portion P' 1, P'2, P'n may be in the form of an elongated strip partially covering a plurality of aligned areas of interest. One or more chips pl 1, pl2, pin may then be formed aligned in each of the areas of interest belonging to the same row or column (see [Fig. 11B]).

[0119] In other embodiments, as illustrated in [Fig. 12A], which is an enlargement of [Fig. 5], each tile and transferred tile portion P' 1 can be arranged so as to cover a respective corner of four distinct areas of interest of the receiving substrate arranged in a square, and a chip pl, pl2, pl3, pl4 is formed from said tile on each corner of the respective area of ​​interest (see [Fig. 12B]).

[0120] Naturally, these different configurations can be combined. For example, it is possible to transfer portions of paving stones oriented differently (for example perpendicular two by two) depending on the areas of interest to be covered.

[0121] The method therefore offers great latitude for the formation of chips depending on the components to be formed there. Application examples

[0122] The present invention presents various particularly advantageous application cases, notably in the field of microelectronics.

[0123] The method can make it possible to arrange chips in a sparsely distributed manner on a 300 mm diameter receiving substrate. Said receiving substrate can be a silicon substrate or a silicon on insulator (SOI) type substrate.

[0124] In photonic applications, the active layer of the receiving substrate may comprise a photonic circuit comprising passive or active devices, for example one or more waveguide(s), one or more multiplexer(s), one or more micro-resonators, etc. The chips transferred onto this layer may be made of InP, which is a material more suitable than silicon for the epitaxial growth of a stacking of III-V materials to form a laser.

[0125] In radio frequency (RF) applications, the active layer of the receiving substrate may comprise components operating at relatively low frequencies, while the chips, which are advantageously made of InP or GaN, may comprise components operating at higher frequencies.

[0126] In micro-LED applications, the size of the GaN chips is advantageously less than 50 pm.

Claims

Claims

1. A method of manufacturing a structure comprising at least two chips (pl, pl2, pl3, pl4) on a receiving substrate (3), comprising: - forming a pseudo-donor substrate (10) by placing at least one tile (PI, P2, P3) of at least one donor substrate (2) on a support substrate (1); - bonding said pseudo-donor substrate (10) to a receiving substrate (3) via the tiles so that each tile at least partially covers at least two distinct areas of interest (Zl, Z2, Zn) of the receiving substrate (3); - transferring a portion (P'1, P'2, P'3) of said tiles (PI, P2, P3) to the receiving substrate (3); - at least one step of chemical-mechanical polishing of the tiles (PI, P2, P3) of the pseudo-donor substrate and / or of the portions of tiles transferred to the receiving substrate;- after said at least one chemical-mechanical polishing step, removing material from said portions (P' 1, P'2, P'3) of tiles so as to divide each portion of tile into at least two chips (pll, pl2, pl3, p 14) each arranged on a respective area of interest (Zl, Z2, Zn).;

2. Method according to claim 1, wherein, after the etching step, the coverage rate of the chips (pl, pl2, pl3, pl4) on the receiving substrate (3), i.e. the ratio between the total surface area of the chips and the total surface area of the receiving substrate, is less than 50%, preferably less than 30%.

3. Method according to one of claims 1 or 2, in which the coverage rate of the tiles (PI, P2, P3) on the pseudo-donor substrate (10), i.e. the ratio between the total surface area of the tiles and the total surface area of the support substrate, is greater than 50%, preferably greater than 75%.

4. Method according to one of claims 1 to 3, in which each block (PI, P2, P3) has a side of length greater than or equal to 5 mm, preferably greater than or equal to 8 mm, and preferably greater than or equal to 10 mm.

5. Method according to one of claims 1 to 4, in which each chip (pl 1, pl2, pl3, pl4) has a side of length less than or equal to 5 mm, preferably less than or equal to 3 mm, and preferably less than or equal to 1 mm.

6. Method according to one of claims 1 to 5, in which the distance between two adjacent blocks (PI, P2, P3) is less than or equal to 3 mm, preferably less than or equal to 1 mm.

7. Method according to one of claims 1 to 6, in which the distance between two adjacent chips (pl, pl2, pl3, pl4) is greater than or equal to 3 mm, preferably greater than or equal to 5 mm.

8. Method according to one of claims 1 to 7, in which each tile at least partially covers two distinct areas of interest of the receiving substrate and a chip is formed from said tile on each respective area of interest.

9. Method according to one of claims 1 to 7, in which each tile covers a respective corner of four distinct areas of interest of the receiving substrate arranged in a square or rectangle, and a chip is formed from said tile on each corner of the respective area of interest.

10. Method according to one of claims 1 to 7, in which each tile is in the form of a strip at least partially covering at least three aligned areas of interest of the receiving substrate and a chip is formed from said tile on each respective area of interest.

11. Method according to one of claims 1 to 10, in which the support substrate (1) and the receiving substrate (3) have a substantially identical diameter, greater than the diameter of the donor substrate (2).

12. Method according to one of claims 1 to 11, in which the bonding of the pseudo-donor substrate (10) on the recipient substrate (3) is carried out by molecular adhesion.

13. Method according to one of claims 1 to 12, in which the transfer of each portion (P' 1, P'2, P'3) of block comprises successively the formation of a weakening zone (11) by implantation of atomic species in each block (PI, P2, P3) of the pseudo-donor substrate (10) to define a portion (P' 1, P'2, P'3) of block to be transferred, the bonding of the pseudo-donor substrate (10) on the receiving substrate (3) by means of the blocks (PI, P2, P3), and the detachment of each block along the weakening zone (11).

14. Method according to one of claims 1 to 12, in which the transfer of each portion (P' 1, P'2, P'3) of the block comprises thinning by grinding and / or etching of each block (PI, P2, P3) of the pseudodonor substrate.

15. Method according to one of claims 1 to 14, in which each block (PI, P2, P3) has a thickness of between 20 pm and 1000 pm, preferably between 100 pm and 700 pm, and the transferred portion of each block has a thickness between 30 nm and 1.5 pm.

16. Method according to one of claims 1 to 15, in which each tile (PI, P2, P3) comprises: - a semiconductor material, such as a III-V material, in particular indium nitride (InN), gallium nitride (GaN), aluminum nitride (AIN), indium arsenide (InAs), gallium arsenide (GaAs), aluminum arsenide (AlAs), indium phosphide (InP), gallium phosphide (GaP) or aluminum phosphide (AlP), or a IV or IV-IV material, in particular germanium or silicon carbide (SiC), - a piezoelectric material, such as lithium tantalate (LiTaO3), lithium niobate (LiNbO3), potassium-sodium niobate (KxNabx NbO3 or KNN), barium titanate (BaTiO3), quartz, lead zirconate titanate (PZT), a compound of lead-magnesium niobate and lead titanate (PMN-PT), zinc oxide (ZnO), aluminum nitride (AIN) or aluminum scandium nitride (AIScN), and / or - an electrically insulating material,such as diamond, strontium titanate, yttria zirconia or sapphire.,

17. Method according to one of claims 1 to 16, comprising a step of forming by epitaxy at least one epitaxial layer on each portion of tile, the removal of material to divide each portion of tile into chips being carried out after said epitaxy step.

18. Method according to one of claims 1 to 17, wherein the removal of material comprises: - the formation of a mask comprising a protective film partially covering said portions of tiles according to a pattern defining said chips in each portion of tile and at least one opening defining a space to be formed between two chips; - the etching of each portion of tile through each opening of the mask so as to form said space to separate said chips from each other.

19. The method of claim 18, wherein the etching is performed using an etching solution and the mask is formed from a photosensitive resin.

20. The method of claim 18, wherein the etching is performed using an ion beam and the mask is formed of a metal.

21. A method according to any one of claims 1 to 17, wherein the removal of material is carried out selectively by a focused beam of ions, said beam being controlled to scan only the regions of the portions of paving stones to be removed.

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