Process for structuring a substrate

Abstract

Method for structuring a substrate The present description relates to a method comprising the following steps: Bonding a handle substrate (100) comprising raised elements (120) with a substrate of interest (200) comprising a support substrate (210) covered by a thin layer (220) comprising a material sensitive to an etching agent, whereby the thin layer (220) comprises first zones (Z1) not covered by the raised elements (120) and second zones (Z2) covered by said elements (120), Bringing the assembly obtained into contact with a solution comprising a hydrophobic agent, to cover the first zones (Z1) with a hydrophobic film (130), Separating the two substrates (100, 200), Bringing the substrate of interest (200) into contact with a solution containing the etching agent, whereby the material sensitive to the etching agent present in the second zones (Z2) is etched and hydrophobic film (130) is formed. patterns (250) in relief. Figure for the abstract: Fig. 1G.

Description

Title of the invention: Method for structuring a substrate Technical field

[0001] The present description relates generally to the field of microelectronics and more particularly to the production of patterns on a substrate with a view to manufacturing microelectronic components. Prior art

[0002] The development of microelectronic components requires the production of patterns on a substrate by photolithography.

[0003] Photolithography is carried out through different steps using a resin: spreading the resin on a substrate, exposing the resin using a mask, developing, etching and then removing the resin (or "stripping"). The removal step (or cleaning the resin) is a complex step because it requires finding a cleaning agent that is sufficiently aggressive to perfectly clean the resin while preserving the integrity of the different surfaces.

[0004] For each substrate on which microelectronic components must be produced, these different steps are repeated. However, these steps are not only long to implement, but, in addition, they generate significant costs, due in particular to the use of resins, solvents and cleaning solutions used. Summary of the invention

[0005] There is a need to obtain a method which makes it possible to produce patterns on a substrate while limiting the costs and duration of the method compared to current methods.

[0006] This aim is achieved by a method of producing patterns on a substrate comprising the following steps: a. Bonding a handle substrate to a substrate of interest, the handle substrate comprising a base and raised elements covering the base, the substrate of interest comprising a support substrate covered by a thin layer, the thin layer comprising a material sensitive to an etchant, whereby the thin layer comprises first areas not covered by the raised elements and second areas covered by the raised elements, b. Forming a hydrophobic layer on the first areas of the thin layer, for example by bringing the assembly obtained in step a) into contact with a solution comprising a hydrophobic compound, c. Separate the handle substrate from the substrate of interest, d. Contacting the substrate of interest with an aqueous solution comprising the etching agent, whereby the material sensitive to the etching agent present in the second areas of the thin layer is etched and relief patterns are formed.

[0007] One embodiment provides that the thin layer comprises a base material, the base material preferably being a semiconductor material, for example silicon, or an oxide, for example silicon oxide.

[0008] Another embodiment provides that the thin layer comprises a base material, for example an oxide, preferably a silicon oxide, in which pads are arranged, preferably metal pads, and even more preferably copper pads.

[0009] An alternative embodiment provides that the material sensitive to the etching agent is the base material.

[0010] Another embodiment variant provides that the material sensitive to the etching agent corresponds to the pads.

[0011] Another embodiment provides that the thin layer comprises barriers, preferably metal barriers, and more particularly copper barriers, forming lateral protection all around the second zones.

[0012] According to an alternative embodiment, during the etching step, the barriers and the pads are etched.

[0013] According to another variant embodiment, the method comprises, after step c), an additional step during which the barriers and the pads are etched.

[0014] Another embodiment provides that the method comprises a subsequent step during which the handle substrate is used to structure another substrate of interest.

[0015] Another embodiment provides that the hydrophobic layer comprises at least one compound comprising one or more halogen atoms and a carbon chain comprising at least 5 carbon atoms.

[0016] Another embodiment provides that the hydrophobic compound is chosen from silanes, in particular chlorosilanes, and polymers, preferably fluorinated polymers. Brief description of the drawings

[0017] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0018] Figures 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I and 1J represent, in a manner schematic, different steps for forming patterns on a substrate, according to a particular embodiment of the invention;

[0019] [Fig.2] is a photographic image of a plate comprising hydrophobic zones and hydrophilic zones, obtained according to a particular embodiment of the invention, and on which an aqueous solution has been deposited;

[0020] Figures 3A, 3B, 3C and 3D schematically represent different steps of a method of structuring a substrate of interest according to another particular embodiment, the substrate being represented in section;

[0021] Figures 3E and 3F represent, schematically and in top view, the substrate shown in Figures 3C and 3D respectively, the dotted lines representing the position of the hydrophobic layer;

[0022] Figures 4A, 4B, 4C and 4D schematically represent different steps of a method of structuring a substrate of interest according to another particular embodiment, the substrate being represented in section;

[0023] Figures 4E and 4F represent, schematically and in top view, the substrate shown in Figures 4C and 4D respectively, the dotted lines representing the position of the hydrophobic layer; and

[0024] Figures 5A, 5B and 5C schematically represent different steps of a method of structuring a substrate of interest according to another particular embodiment, the substrate being represented in top view and the dotted lines representing the position of the hydrophobic layer. Description of the embodiments

[0025] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0026] For the sake of clarity, only the steps and elements useful for understanding the embodiments described have been represented and are detailed.

[0027] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0028] In the following description, when referring to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., it is made reference unless otherwise specified to the orientation of the figures in a normal position of use.

[0029] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0030] We will now describe in more detail the method of producing patterns on a substrate, firstly referring to Figures 1A to 1J.

[0031] The method comprises the following steps: a. Bonding a handle substrate 100 to a substrate of interest 200, the handle substrate 100 comprising a base 110 and raised elements 120 covering the base 110, the substrate of interest 200 comprising a support substrate 210 covered by a thin layer 220, the thin layer 220 comprising a material sensitive to an etching agent, whereby the thin layer 220 comprises first zones Z1 not covered by the raised elements 120 and second zones Z2 covered by the raised elements 120 (figures 1A and 1B), b. Forming a hydrophobic layer 130 on the first zones ZI of the thin layer 220, for example by bringing the assembly obtained in step a) into contact with a solution comprising a hydrophobic compound (typically by immersion) (figures IC and 1D), c. Separate the handle substrate 100 from the substrate of interest 200 ([Fig.lE]), d. Bringing the substrate of interest 200 into contact with an aqueous solution 300 comprising the etching agent, the hydrophobic layer 130 protecting the first zones Z1, whereby the material sensitive to the etching agent present in the second zones Z2 of the thin layer 220 is etched and relief patterns 250 are formed (figures 1F to 1H), e. If necessary, remove excess solution 300 ([Fig. II]) and remove the hydrophobic layer 130 ([Fig. U]).

[0032] The handle substrate 100 forms a hard mask. It makes it possible to form patterns 250 on the substrate of interest without implementing photolithography steps. The method is thus simple and quick to implement.

[0033] In addition, with a single handle substrate 100, it is possible to form patterns on several substrates (wafers). The handle substrate is reusable, which further reduces process costs.

[0034] Prior to step a), it is possible to carry out one or more pre-treatments on the surface of the handle substrate 100 and / or on the surface of the substrate of interest 200 so as to make them compatible with direct bonding.

[0035] The pretreatment can be chosen from the following pretreatments: thermal annealing, plasma, polishing and wet cleaning.

[0036] By way of example, it is possible to form an oxide layer on the surface of the handle substrate 100 and / or to carry out a polishing step on the handle substrate 100 and / or on the substrate of interest 200 to obtain a roughness compatible with direct bonding (typically a roughness less than 0.5 nm RMS). It is possible to implement methods which combine, for example, a plasma and an aqueous solution, in particular an oxygen plasma followed by CARO wet cleaning (H2SO4, H2O2 in a proportion of 5:1) associated with SCI (H2O, NH3, H2O2 in a proportion of 5:1:1 at 70°C).

[0037] During step a), the handle substrate 100 and the substrate of interest 200 are brought into contact to be bonded.

[0038] The two substrates 100, 200 can be assembled by direct bonding. The use of marks on the substrates 100, 200 can facilitate their alignment. An accuracy of approximately 100 nm can be achieved. It is also possible to align them, without using marks, by using the edges of the substrates as well as their notch (or 'notch'). The accuracy is lower (+ / - 50 pm) but sufficient for certain applications.

[0039] Direct bonding can be carried out at atmospheric pressure (i.e. 1013.25 hPa) or under vacuum. The assembly does not necessarily need to be consolidated by heat treatment. However, annealing, at a temperature preferably below 200°C, can advantageously be carried out.

[0040] The handle substrate 100 comprises a base 110 and raised elements 120 (pillars or columns). The surface of the elements 120 may be of different shapes. It may be square, rectangular or even circular. The raised elements 120 have, for example, a height of between 1 pm and 200 pm or more specifically between 10 pm and 100 pm. These elements 120 are preferably spaced apart by more than 10 pm or even more than 50 pm in order to allow the infiltration of the etching agent (gaseous or liquid) by capillarity within the network formed by the raised elements 120.

[0041] The base 110 and the raised elements may be made of different materials. Preferably, they are made of the same material.

[0042] The handle substrate 100 is preferably obtained from a solid substrate. It may be a substrate made of metal or semiconductor material for example.

[0043] In particular, the raised elements 120 of the handle substrate 100 can be produced by means of a photolithography step, for example by means of the following sub-steps: - locally deposit a resin on a substrate, - etch the parts of the substrate not covered by the resin to form raised elements 120 in the substrate, - remove the resin, - possibly, cut out the substrate.

[0044] Trimming the edge of the plate makes it possible to avoid possible edge contact between the handle substrate 100 and the substrate of interest 200.

[0045] The trimming can be carried out for example by photolithography / etching, or by mechanical trimming using a diamond saw. The width of the trimming is, for example, between 1 and 5 mm and / or its depth is, for example, between 100 and 250 μm.

[0046] In step b), a hydrophobic layer is formed on the first zones (Zl) of the thin layer (220). The layer can also be called a film.

[0047] The choice of the hydrophobic layer 130 will depend, in particular, on the substrate of interest 200 and the etching solution 300.

[0048] The hydrophobic layer 130 has, for example, a thickness of between 2 nm and 100 nm.

[0049] The hydrophobic layer 130 can be obtained from a polymer, a silyl (also called organosilyl) or a silane.

[0050] The chosen hydrophobic compound preferably comprises one or more halogen groups, in particular fluorine or chlorine groups. Preferably, the hydrophobic compound comprises a carbon chain of at least 5 carbon atoms.

[0051] The silane can be a chlorosilane such as octadecyltrichlorosilane (OTS = CH3 (-CH2)i7-SiCl3) marketed by the company Sigma Aldrich.

[0052] The polymers may be fluorinated polymers such as, for example, the Novec™ 1720 EGC polymer marketed by the company 3M™, Optool marketed by the company DAIKIN and the Novec™ 2202 EGC polymer marketed by the company 3M™. The hydrophobic compound may be chosen from chlorosilanes such as per-fluorodecyltrichlorosilane (FDTS = Cl3Si(CH2)2(CF2)7CF3) marketed by the company Sigma-Aldrich, perfluorodecyldimethylchlorosilane (FDDMCS = CF3(CF2)7(CH2)2(CH3)2SiCl) marketed by the company Sigma-Aldrich.

[0053] Preferably, the hydrophobic layer 130 is deposited by liquid means, by immersing the assembly formed by the handle substrate 100 and the substrate of interest 200 in a solution containing the hydrophobic compound(s) intended to form the hydrophobic layer 130 on the first zones Z1 of the thin layer 220. The liquid infiltrates within the network formed by the raised elements 120. The trimming facilitates the entry of the liquid at the edge of the bonded structures.

[0054] After step b), a rinsing step and, optionally, a drying step can be carried out. Drying can be carried out by centrifugation.

[0055] Annealing can allow the hydrophobic layer 130 to be dried and / or stabilized.

[0056] During step c), the handle substrate 100 is separated from the substrate 200. The assembly can be disassembled by inserting, for example, a wedge between the two substrates 100, 200.

[0057] The handle substrate 100 can be used in a new bonding / etching cycle. Cleaning is advantageously carried out between each use.

[0058] For example, it is possible to recycle it by implementing an oxygen plasma treatment followed by wet cleaning.

[0059] Alternatively, since the bases of the raised elements 120 of the handle substrate 100 have not been exposed to the hydrophobic compound, they are still compatible with direct bonding. The handle substrate 100 can therefore be directly reused.

[0060] During step d), the substrate of interest 200 is brought into contact with an aqueous solution 300 comprising the etching agent, for example by immersion.

[0061] The duration during which the second zones Z2 are in contact with the etching solution 300 will depend on the thickness of the material to be etched.

[0062] During the etching step, it is possible for the hydrophobic layer 130 to thin by a few tens of percent. The duration of the etching step and / or the thickness of the hydrophobic layer 130 will be chosen so as not to lead to the complete removal of the hydrophobic layer 130.

[0063] It is also possible to immerse the substrate 200 entirely in the solution 300 and then remove it immediately afterwards. The first zones Z1 being covered by the hydrophobic layer 130, when the plate is removed, dewetting of the aqueous solution 300 on the first hydrophobic zones Z1 occurs and the solution 300 is confined on the second zones Z2 devoid of hydrophobic coating ([Fig.lG] and [Fig.2]).

[0064] Thus, only the material sensitive to the etching agent present in the second zones Z2 is etched ([Fig. 1H]). Relief patterns 250 are thus formed.

[0065] At the end of step d), the assembly can be rinsed and then dried. Drying can be carried out by centrifugation.

[0066] If necessary, it is possible to repeat step d). This is particularly advantageous in the case where the support substrate 210 is covered by a stack of several thin layers. Thus, it is possible to use several etching agents to etch the different thin layers of the stack.

[0067] During step e), the hydrophobic layer 130 can be removed from the zones ZI. It is, for example, possible to use an oxygen plasma followed by CARO wet cleaning associated with an SCI.

[0068] We will now describe in more detail the substrate of interest and its different possible configurations.

[0069] The substrate of interest 200 comprises the support substrate 210 covered by the thin layer 220 comprising at least one material sensitive to an etching agent.

[0070] The substrate of interest 200 may be an SOI ('Silicon on Insulator') substrate, i.e. comprising a support substrate 210 covered by a thin layer of oxide buried and a layer of silicon 220. The thin oxide layer can act as an etching stop layer (vertical etching).

[0071] Alternatively, it may be a solid substrate 210 made of semiconductor material (silicon for example) covered with a dielectric layer 220, in particular an oxide layer (silicon oxide in particular).

[0072] For certain applications, the thin layer 220 may comprise a base material (oxide in particular) and pads 230, in particular metal pads (FIGS. 3A to 3F). The pads 230 may be distributed regularly or irregularly.

[0073] In the case where the etching-sensitive material corresponds to the pads 230, the base material is not etched, and a thin layer 220 is obtained comprising a plurality of holes (blind or passing through the thin layer 220) and raised patterns 250 (FIGS. 3A to 3F). The holes are obtained after etching the pads 230. The raised patterns 250 correspond to the first parts ZI of the thin layer 220 which was protected by the hydrophobic layer 130.

[0074] In the case where the etching-sensitive material corresponds to the base material, the pads 230 are not etched, and a support substrate 210 is obtained covered by pads at the level of the second zones Z2 and by patterns 250 at the level of the first zones Z1. The patterns 250 may comprise the base material and the pads.

[0075] The pads 230 may be surrounded by a protective layer to protect them during the etching step. For example, layers of Ti and TiN or Ta and TaN may surround copper pads 230. Specific types of etching may then be used for these materials.

[0076] According to a particular embodiment, elements 240 may be arranged within the thin layer 220. These elements 240 form vertical walls in the thin layer 220. These elements 240 surround the first zones ZI. These are protective barriers 240 making it possible to stop lateral over-etching, which can sometimes accompany the vertical etching of the etched material. The width of this barrier will be chosen so as to be sufficiently large to stop over-etching. The elements 240 may have identical or different shapes. They are, of course, made of a material different from the material sensitive to the etching agent.

[0077] The positioning of the elements 240 is chosen so as to surround the first zones ZI to be protected.

[0078] When the thin layer 220 comprises protective barriers 240, the method may comprise, after step d), an additional step during which the protective barriers 240 are removed.

[0079] According to a particular embodiment, the thin layer 120 comprises a base material, protective barriers 240 and pads 230 (FIGS. 4A to 4F and 5A to 5C).

[0080] According to a first variant embodiment, the protective barriers 240 and the pads 230 are sensitive to the same etching agent. The protective barriers 240 are preferably made of the same material as the pads 230. Even more preferably, it is a metal, such as copper. Advantageously, the base material is an oxide, for example a silicon oxide. The protective barriers 240 and the pads 230 can thus be removed during a single etching step ([Fig.4A] to 4F). A thin layer 220 is thus obtained comprising a plurality of holes (blind or passing through the thin layer 220) at the level of the second zones Z2. The first zones Z1 of the thin layer 220 opposite the raised elements 120 are preserved during the etching step and raised patterns 250 are formed.

[0081] According to a second embodiment variant shown in FIGS. 5A to 5C, the base material is sensitive to the etching agent. The protective barriers 240 of the base material and the pads 230 are not sensitive to the etching agent ([Fig. 5A]). The protective barriers 240 and the pads 230 may be made of the same material or different materials. For example, the protective barriers 240 and the pads 230 are made of metal, preferably copper. The base material is, for example, an oxide, and in particular a silicon oxide. During the etching step, the base material present in the second zones Z2 is etched. The protective barriers 240 and the metal pads 230 not sensitive to the etching element are preserved during the etching step ([Fig. 5B]). A structure is obtained comprising relief patterns 250 surrounded by protective barriers 240.The relief patterns 250 comprise the base material in which the pads 230 are dispersed. The patterns 250 are surrounded by the protective barriers 240. Between the patterns 250, at the level of the second zones Z2, the support substrate 210 is covered by the metal pads 230 ([Fig.5B]).

[0082] It is possible to carry out an additional etching step (or several additional etching steps) to remove the metal pads 230 and / or the protective barriers 240 ([Fig.5C]).

[0083] The metal barriers 240 and / or the metal pads 230 can be inserted into the oxide layer, for example with a Damascene type process.

[0084] In particular, it is possible to choose metallic barriers 240 and / or metallic pads 230 made of copper inserted in a layer of silicon oxide.

[0085] The metal barriers 240 and / or the metal pads 230 may be formed, for example, by physical vapor deposition (or PVD for “Physical Vapor Deposition”) and / or by electrochemical deposition (ECD).

[0086] Preferably, to form copper elements 230 by ECD, layers of Ti, TiN and Cu will be deposited beforehand by PVD. Deposition by ECD makes it possible to form elements of greater thickness than PVD. It is also possible to replace the layers of Ti and TiN with layers of Ta and TaN. The layers of Ti / TiN or Ta / TaN act as a barrier to the diffusion of copper into the silicon.

[0087] The different variants of the method described above lead to obtaining a substrate of interest comprising a support substrate covered by the relief patterns 250. The thickness of the patterns depends on the intended application. The patterns can be formed from the base material ([Fig.U]) or from the base material in which pads 230 are dispersed (Figures 3D, 3F, 4D, 4F). A protective barrier 240 can surround the patterns 250 ([Fig.5B]).

[0088] Apart from the 250 patterns, several variant embodiments are possible, and in particular:

[0089] - the support substrate 210 can be covered with a thin layer 220 having blind holes (figures 3F, 4F) or through holes said layer 220,

[0090] - pads 230 can be positioned on the support substrate 210 ([Fig.5B]),

[0091] - the support substrate 210 may have a free surface (i.e. outside the patterns, no element covers the support substrate 210) (figures 1J, 5C).

[0092] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0093] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

[0094] Illustrative and non-limiting examples of different embodiments

[0095] In the following examples, the substrates are made from silicon wafers 200 mm in diameter.

[0096] Example 1

[0097] The handle substrate 100 is manufactured from a silicon wafer that has undergone oxidation so as to obtain a 2 pm film of silicon oxide on the surface. A photolithography / etching process makes it possible to form relief elements 120 of 10 x 10 mm2 with a thickness of 100 pm. The edge of the substrate 100 is trimmed using a diamond saw. The trimming has a width of 3 mm and a depth of 200 pm. The oxide surface of the wafer is cleaned by an O2 plasma followed by CARO, SCI wet cleaning so as to make it compatible with a direct bonding process.

[0098] The substrate of interest 200 is an SOI wafer comprising a bulk substrate 210 covered by a silicon film 220 with a thickness of 205 nm and a buried oxide layer of 400 nm. The substrate of interest 200 undergoes wet cleaning so as to make it compatible with a direct bonding process.

[0099] The two substrates 100, 200 are bonded directly. The assembly is immersed for 2 min in a solution of OTS in isooctane. The assembly is then rinsed by immersion in isooctane then dried by centrifugation. A hydrophobic film 130 is formed on the zones ZI of the thin layer 220 not covered by the raised elements 120 of the handle substrate 100.

[0100] The handle substrate 100 is dismantled by inserting a wedge into the structure.

[0101] A plate 200 is obtained comprising hydrophobic zones ZI outside the zones Z2 which were protected by the raised elements 120 of the handle substrate 100.

[0102] This plate 200 is dipped in an aqueous solution of TMAH at 5% by mass. After removing it from the liquid, the plate 200 is placed horizontally for 3 minutes on a heating plate at 70° then rinsed in water and rinsed by centrifugation. The layer of silicon 200 exposed to the TMAH is etched down to the buried oxide layer which acts as a stop layer. The hydrophobic film 130 is removed by an oxygen plasma treatment and the surface is cleaned by a wet process (CARO and SCI).

[0103] The obtained silicon plate 200 has 250 patterns (pads) of silicon measuring 10 x 10 mm2 having a thickness of 205 nm.

[0104] Example 2

[0105] The handle substrate 100 is obtained from a silicon wafer as described in example 1. It has rectangular relief elements 120 of 10 x 5 mm2 with a thickness of 15 μm.

[0106] A wafer (substrate) 200 undergoes oxidation so as to form a 100 nm oxide film 220 on its surface. The substrate 200 is wet cleaned so as to make it compatible with a direct bonding process.

[0107] The two substrates 100, 200 are directly bonded. The assembly obtained is immersed for 2 min in the liquid 310 NOVEC 1720 EGC. The assembly is then rinsed by immersion in the solvent NOVEC 7100 EGC and then dried by centrifugation. The handle substrate 100 is dismantled by inserting a wedge into the structure. The substrate of interest 200 undergoes a heat treatment of 15 min at 135°C.

[0108] A substrate of interest 200 is obtained, the thin layer 220 of which comprises hydrophobic zones ZI outside the zones Z2 initially protected by the raised elements 120 of the handle substrate 100.

[0109] The substrate of interest 200 is then immersed in a 5% volume aqueous HF solution. After removing it from the liquid, the plate 200 is placed horizontally for 3 min, then rinsed by immersion in water and dried by centrifugation. The portion of the silicon oxide 220 exposed to the HF solution is etched. The hydrophobic film 130 is removed by an oxygen plasma treatment and the surface is cleaned wet (CARO and SCI).

[0110] A silicon substrate 200 is obtained which has rectangular silicon oxide patterns 250 (plots) of 10 x 5 mm2 with a thickness of 100 nm. [YES] Example 3

[0112] A handle substrate 100 is manufactured from a silicon wafer as described in example 1. The substrate has cylindrical elements 120 of 5 mm diameter with a thickness of 60 μm.

[0113] On a wafer, 400 nm of oxide is deposited from TEOS. Then, layers of Ti, TiN and Cu with a thickness of 10, 50 and 200 nm are deposited by PVD. Finally, an electrochemical treatment by ECD allows the subsequent deposit of a 300 nm Cu film. A copper polishing step removes a 200 nm thickness of copper and prepares the surface of the substrate for direct bonding.

[0114] The two substrates 100, 200 are directly bonded. The assembly is immersed for 2 min in a solution 310 of FDTS in isooctane. The assembly is then rinsed by immersion in isooctane and then dried by centrifugation. The handle substrate 100 is removed by inserting a wedge into the structure.

[0115] On the plate 200, hydrophobic zones ZI are obtained outside the zones Z2 protected by the raised elements 120 during bonding with the handle substrate 100.

[0116] The plate 200 is immersed in an aqueous solution of DSP (H2SO4 / H2O2 / H2O in a proportion of 1 / 2 / 50) so as to etch the copper layers. After the liquid has left, the plate 200 is placed horizontally for 3 min. The assembly is then rinsed by immersion in water and then dried by centrifugation. The copper layer 220 is etched according to the patterns defined by the raised elements 120 of the handle substrate 100.

[0117] The plate 200 is then immersed in an SCI solution. After the liquid has left, the plate 200 is placed horizontally on a heating plate at 70°C for 2 min then rinsed and dried. The Ti and TiN layers are etched according to the patterns defined by the raised elements 120 of the handle substrate 100. The hydrophobic film 130 is removed by an oxygen plasma treatment then the surface is cleaned wet (CARO and SCI).

[0118] A plate of interest 200 is obtained comprising a support substrate 210 made of silicon covered by cylindrical relief patterns 250 (pads) of copper of 5 mm2 having a thickness of 300 nm.

Claims

Claims

1. A method of producing patterns on a substrate comprising the following steps: a. Bonding a handle substrate (100) to a substrate of interest (200), the handle substrate (100) comprising a base (110) and raised elements (120) covering the base (110), the substrate of interest (200) comprising a support substrate (210) covered by a thin layer (220), the thin layer (220) comprising a material sensitive to an etchant, whereby the thin layer (220) comprises first areas (Z1) not covered by the raised elements (120) and second areas (Z2) covered by the raised elements (120), b. Forming a hydrophobic layer (130) on the first zones (Zl) of the thin layer (220), for example by bringing the assembly obtained in step a) into contact with a solution comprising a hydrophobic compound, c. Separating the handle substrate (100) from the substrate of interest (200), d. Contacting the substrate of interest (200) with an aqueous solution (300) comprising the etching agent, whereby the material sensitive to the etching agent present in the second zones (Z2) of the thin layer (220) is etched and relief patterns (250) are formed.

2. A method according to claim 1, characterized in that the thin layer (220) comprises a base material, the base material preferably being a semiconductor material, for example silicon, or an oxide, for example silicon oxide.

3. Method according to any one of the preceding claims, characterized in that the thin layer (220) comprises a base material, for example an oxide, preferably a silicon oxide, in which pads (230) are arranged, preferably metal pads (230), and even more preferably copper pads (230).

4. A method according to claim 3, characterized in that the material sensitive to the etching agent is the base material.

5. Method according to claim 3, characterized in that the material sensitive to the etching agent corresponds to the pads (230).

6. Method according to any one of the preceding claims, characterized in that the thin layer (220) comprises barriers (240), preferably metallic barriers (240), and more particularly copper barriers, forming lateral protection all around the second zones (Z2).

7. Method according to claims 5 and 6, characterized in that during the etching step, the barriers (240) and the pads (230) are etched.

8. Method according to claims 4 and 6, characterized in that the method comprises, after step c), an additional step during which the barriers (240) and the pads (230) are etched.

9. A method according to any preceding claim, characterized in that the method comprises a subsequent step in which the handle substrate (100) is used to structure another substrate of interest.

10. Method according to any one of the preceding claims, characterized in that the hydrophobic layer comprises at least one compound comprising one or more halogen atoms and a carbon chain comprising at least 5 carbon atoms.

11. Method according to the preceding claim, characterized in that the hydrophobic compound is chosen from silanes, in particular chlorosilanes, and polymers, preferably fluorinated polymers.

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