METHOD FOR PRODUCING A NANOIMPRINT MOLD AND CORRESPONDING MOLD

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of nanometric imprint lithography, also known as nanoimprint. It finds a particularly advantageous application in the manufacture of master molds used to produce molds for producing patterns with high resolution, i.e. patterns whose critical dimensions are a few hundred nanometers (10 -9< meters), or even a few tens of nanometers. STATE OF THE ART

[0002] Nano-imprint lithography techniques rely on printing a deformable resin onto a substrate using a mold. The mold contains patterns that are transferred into the resin during printing. These patterns are commonly measured in tens of nanometers. The nano-imprinted resin film can be used as an etching mask for subsequent manufacturing steps, such as microelectronic, optical, or micromechanical devices.

[0003] Standard nanoscale printing techniques can be differentiated according to three criteria: Direct or indirect replication

[0004] For direct replication, the mold is placed directly in contact with the resin film to be structured. This results in reverse polarity between the mold and the structured resin.

[0005] For indirect replication, the patterns of a so-called master mold are copied into a secondary mold, which will in turn be printed in the resin to be structured. The secondary mold can be used once or several times depending on the technology. This process has become the benchmark for industrial solutions because it limits the risk of damage or even breakage of the master mold. Thermal or UV process

[0006] The choice of a process involving a resin solidification step using thermal or UV means depends on the nature of the resin to be structured. Thermal processes are generally used for shaping thermoplastic resins that are not liquid at room temperature, or for crosslinking thermosetting resins. UV processes are generally used for crosslinking photosensitive resins. The combination of these two types of processes is possible for hybrid resins that may require photo and thermoactivation. Rigidity of molds and substrate

[0007] The molds and / or the substrate can be rigid, that is to say, be little deformable under the action of their own weight for thicknesses of a few hundred micrometers and have a Young's modulus greater than 10 GPa (for example by being based on silicon or aluminum).

[0008] The molds in particular can be flexible, that is to say, they can be deformed macroscopically under the action of their own weight for thicknesses of up to a few hundred micrometers and have a Young's modulus of less than 10 GPa (for example, by being based on polyethylene terephthalate PET, polycarbonate PC, etc.).

[0009] Regardless of the technique used, nano-imprinting involves displacements and / or flow of resin during pattern transfer, so that the free spaces between the patterns of the mold are filled by the resin. In practice, the person skilled in the art chooses the initial quantity of resin so as to leave a residual thickness 30 under the patterns 31a, 31b, as illustrated for example in the Figure 1A .

[0010] This resin filling implies that the quantity of resin required depends on the density of patterns if the height of the latter is constant. Therefore, if the density of the patterns varies depending on the locations on a mold, then the volumes of resin to fill them and obtain a homogeneous residual thickness will be different, or, with an equivalent initial volume of resin, the residual thickness of resin will not be homogeneous in the printed resin layer, as illustrated under patterns 31a and 31b in Figure 1A This is particularly the case for technologies that use spin coating (generally referred to by the English term spin-coating ) for resin spreading, whereby the resin thickness is substantially constant at all points on the substrate surface before printing.

[0011] The variation in the residual thickness induces limitations for the etching of the patterns 31a, 31b in the substrate 3. Indeed, this etching generally comprises a preliminary step of removing the residual thickness 30 of resin by an anisotropic process. The complete removal of this residual thickness 30 generally occurs first in the least dense patterns 31a, as illustrated by the Figure 1B , then in the densest 31b patterns, as illustrated by the Figure 1C This leads to a risk of losing critical dimensions of the patterns compared to the mold patterns, and a significant reduction in the amount of resin that can then be consumed when engraving the pattern.

[0012] To avoid this, solutions consist of adapting the height of the patterns on the mold according to the density of the patterns, to obtain a residual thickness of resin that is substantially homogeneous.

[0013] To do this, a first solution consists of separating the patterns to be made into sets of patterns, each set having patterns with a given average density, the sets between them having different pattern densities. One mold per set is then made and the steps of copying the master and depositing the resin are carried out successively per set of patterns, so as to have a homogeneous residual thickness between the different sets.

[0014] A second solution is to produce a master with different pattern heights corresponding to the different densities. On the master to be produced, the patterns to be produced are separated into sets of patterns, each set having patterns with a given average density, the sets between them having different pattern densities. The different sets of patterns in the mold are produced by applying a mask and then successively lithographing each set, so that each set has the appropriate pattern height.

[0015] Regardless of the above solution, these solutions require many steps and are complex to implement. In particular, these solutions present significant constraints in terms of alignment of the different sets of patterns during the successive manufacturing steps. For the alignment of these sets, current equipment generally allows a lateral resolution of between 2 and 10 µm. A resolution of less than 100 nm, and preferably of the order of 10 nm, would be necessary to allow reliable and reproducible alignment.

[0016] US 2019 / 369310 A1 describes a method of manufacturing a mold for nano-imprinting.

[0017] US 2016 / 308020 A1 describes a mold for nano-imprinting.

[0018] There is therefore a need to propose a solution to improve the manufacturing of a mold for nano-imprinting, allowing the residual thickness of resin to be controlled.

[0019] Other objects, features, and advantages of the present invention will become apparent from the following description and accompanying drawings. It is understood that other advantages may be incorporated. SUMMARY OF THE INVENTION

[0020] To achieve this objective, according to one embodiment, a method of manufacturing a mold for nano-imprinting is provided comprising providing a substrate comprising a layer having an upper face and a lower face opposite the upper face.

[0021] The method further comprises at least one ion implantation in at least one portion of the layer, the ion implantation being configured so as to obtain within the layer at least a first portion which is not implanted or which has a first implantation, and at least a second portion which has a second implantation, the first implantation and the second implantation being different, the first and second portions each extending from said upper face, the ion implantation further defining a third non-implanted portion, extending at least from the first portion, and preferably from the first and second portions, to the lower face of the layer.

[0022] After or before implantation, the method comprises producing a so-called etching mask surmounting the upper face and having a plurality of openings.

[0023] After implantation, the method comprises etching the layer configured to have a different etching speed at least between the second portion and the third portion, preferably between the first and second portions and the third portion, so as to etch through the openings of the etching mask a plurality of patterns of different heights in the layer, at least one pattern extending in the first portion and at least one pattern extending in the second portion, the etching being configured to etch in the first portion a first set of patterns and to etch in the second portion a second set of patterns: i. the first set of patterns having a first density D1 of patterns and a first height H1, ii. the second set of patterns having a second density D2 of patterns, and a second height H2, and in which D2>D1.

[0024] Ion implantation makes it possible to modify the etching properties of the second portion, or possibly the first portion, by implanting ions in the layer. Thus, when etching the patterns in each of these portions, the etching speed differing between the implanted and non-implanted portions, possibly between implanted portions of different nature, patterns of different heights are obtained for the same etching step, for example for the same etching time. It is therefore no longer necessary to successively produce the patterns for each pattern height. Alignment constraints are therefore minimized, and preferably avoided.

[0025] The mold manufacturing process is therefore simplified. The mold manufacturing cost is reduced. In addition, the manufacturing process is made more reliable, since the constraints related to the alignment between different patterns of different heights are relaxed.

[0026] According to an example, the first implantation and the second implantation differ by at least one parameter among: an implantation depth, a nature of the implanted ions, an implanted ion dose. Thus, the first and second portions differ by one of these parameters, modifying the etching rate between these portions.

[0027] Another aspect relates to a mold for nano-imprinting comprising a substrate comprising a layer having an upper face and a lower face opposite the upper face and several patterns extending from the upper face, the layer being intended to penetrate into a layer to be printed to transfer the patterns thereto, at least one of the patterns having a height different from another pattern, the layer comprising at least a first non-implanted portion or having a first implantation, and at least a second portion having a second implantation, the first implantation and the second implantation being different, the first and second portions each extending from said upper face, and a third non-implanted portion extending at least from the first portion, and preferably from the first and second portions, to the lower face of the layer,a first set of patterns extending in the first portion and a second set of patterns extending in the second portion, with: , i. the first set of patterns having a first density D1 of patterns and a first height H1, ii. the second set of patterns having a second density D2 of patterns, and a second height H2, and in which D2>D1.

[0028] The mold thus presents the advantages of the manufacturing process according to the first aspect. In particular, the patterns of different heights carried by the layer are made more reliable compared to the patterns that are desired to be obtained by nano-imprinting. The alignments between the patterns of different heights are indeed facilitated thanks to the manufacturing process. Ultimately, compared to known solutions, the proposed mold makes it possible to reduce alignment inaccuracies and improves the overall precision of the printing carried out. The mold therefore makes it possible to simplify nano-imprinting by avoiding multiple printing steps on the substrate to be printed, and to make nano-imprinting more reliable compared to existing solutions using a mold having patterns of different heights. In addition, the cost of the mold is reduced compared to these solutions.

[0029] According to one example, the mold is a so-called master mold, intended to be used for the production of secondary molds. BRIEF DESCRIPTION OF THE FIGURES

[0030] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which: THE Figures 1A to 1C represent steps of pattern transfer and etching to remove the residual thickness of resin after transfer, according to a solution of the existing state of the art. The Figures 2A and 2B represent a cross-sectional view of the substrate comprising an implantation mask having a first thickness E 1 and a second thickness E 2 according to two exemplary embodiments of the method. The Figures 3A and 3B represent a cross-sectional view of the substrate respectively illustrated by the Figures 2A and 2B , after ion implantation according to an example of implementation of the method. The Figure 3Crepresents a cross-sectional view of the substrate illustrated by the Figure 2B , after ion implantation according to another example of implementation of the method than that illustrated by the Figures 3A and 3B . THE Figures 4A to 4C represent a cross-sectional view of the substrate illustrated by the Figure 3A , during the stages of engraving the patterns according to an example of the implementation of the process. The Figures 5A to 5C represent a cross-sectional view of the substrate illustrated by the Figure 3C , during the stages of engraving the patterns according to an example of the implementation of the process. The Figures 6A and 6B represent a cross-sectional view of the substrate after localized ion implantation, according to two other examples of embodiment of the method. The Figures 6C and 6D represent a cross-sectional view of the substrate illustrated by any of the Figures 6A and 6B , during the stages of engraving the patterns according to an example of the implementation of the process. The Figures 6E to 6Grepresent a cross-sectional view of an embodiment in which the mold is a master mold allowing the production of a secondary mold and the pressing of the latter to produce a final pattern. The Figures 7A and 7B represent ion implantation diagrams respectively in silica SiO 2 and in a photoresist. The Figures 8A to 8C represent a cross-sectional view of an embodiment in which the mold is a direct mold and the pressing of the latter to produce a final pattern.

[0031] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. In particular, the relative dimensions of the masks, layers, portions of layers and patterns and openings are not representative of reality. DETAILED DESCRIPTION OF THE INVENTION

[0032] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below.

[0033] According to the invention, the engraving is configured to engrave in the first portion a first set of patterns and to engrave in the second portion a second set of patterns: the first set of patterns having a first density D 1 of patterns and a first height H 1 , the second set of patterns having a second density D 2 of patterns, and a second height H 2 , and D 2 >D 1 , and optionally H 2 >H 1 .

[0034] Thus, for lower pattern density, the height H 1 is lower than the pattern height for higher pattern density. Adapting the height according to the pattern density further improves the homogeneity of the residual resin layer during nano-imprinting.

[0035] The heights of the etched patterns are measured from the top face of the layer to a bottom of the patterns. This measurement is preferably taken in a direction perpendicular to a plane in which the top face mainly extends. Preferably this direction is parallel to the preferred implantation direction.

[0036] According to one example, the etching is configured such that the etching speed of at least the second portion, preferably the first and second portions, is greater than the etching speed of the third non-implanted portion. Thus, the third non-implanted portion forms a braking layer, or even a stopping layer, of the etching, making it possible to control the height of the etched pattern from the implanted portions.

[0037] According to one example, prior to the ion implantation, and preferably before the production of the etching mask, the method comprises the production of a so-called implantation mask on at least a portion of the upper face of the layer, and the ion implantation is at least partly carried out through the implantation mask so that the first implanted portion has a first implantation depth P 1 and the second implanted portion has a second implantation depth P 2 , with P 2 strictly greater than P 1 and P 1 zero or greater than 0.

[0038] The implantation mask creates a height difference on the surface of the layer. During ion implantation, the penetration of ions into the layer will be impacted by the presence or absence of a mask, and the possible variation in the thickness of the implantation mask above the layer. Depending on the implanted location, the ions will therefore progress to different depths. The depth gradient allows the etching speeds of the patterns to be modulated according to the normal to the main extension plane of the upper face. For a low implantation depth, for example, the etched patterns have a smaller height. For a greater implantation depth, for example, the etched patterns have a greater height.

[0039] The implanted depth is measured from the upper face of the layer and in a direction perpendicular to a plane in which the upper face mainly extends. Preferably this direction is parallel to the preferred direction of implantation.

[0040] According to one example, the mold is said to be flexible, that is to say that it is deformable under the action of its own weight and / or a pressing force in a layer of resin. Typically for thicknesses up to a few hundred micrometers and having a Young's modulus for example less than 10 GPa

[0041] In one example, the implantation mask is configured to cover only a portion of the top face of the layer.

[0042] According to an example, P 2 is strictly greater than P 1 , and P 1 is non-zero. Thus, the entire upper face is implanted, at different depths.

[0043] For example, P 2 is strictly greater than P 1 , and P 1 is zero. Thus, a fraction of the upper face is not implanted.

[0044] According to one example, the implantation mask is configured to have a thickness gradient between at least a first thickness E 1 and a second thickness E 2 , with E 1 strictly greater than E 2 and E 2 zero or greater than 0.

[0045] Preferably E 2 is strictly greater than 0. Thus the layer is covered by the mask on the surface of its first portion and its second portion. This improves the quality of the interface between the implantation mask and the substrate after ion implantation. Indeed, if E 2 is zero, then the surface of the layer is not protected during ion implantation at the surface of the second portion. Depending on the implantation conditions, it is possible that the properties of the second portion, unprotected, are different from those of the first portion protected by the implantation mask. Consequently, different etching behaviors may occur. is therefore advantageous that the first and second portions are covered by the implantation mask of non-zero thickness, to obtain a homogeneous property surface at the end of the implantation.

[0046] According to one example, the mask thickness gradient between E 1 and E 2 is substantially equal to the depth difference between P 1 and P 2 .

[0047] According to one example, the first thickness E 1 is substantially between 50 nm and 100 µm. According to one example, the second thickness E 2< is substantially between 0 nm and E1.

[0048] In one example, the method includes removing the mask after implantation and before the etching step.

[0049] According to one example, the ion implantation is configured such that at least the second implantation depth P 2 , and preferably the first P 1 and second P 2 depths, is / are greater than or equal to 30 nm, preferably strictly greater than 30 nm. According to one example, the ion implantation is configured such that at least one, and preferably each, of the first and second implantation depths is less than or equal to 1 µm (10 -6< meter). Preferably, the ion implantation is configured such that at least one, and preferably each, of the first and second implantation depths is between 30 nm and 1 µm.

[0050] Ion implantation can thus be carried out over a depth substantially equal to the height of the pattern that will be obtained by etching. This is particularly advantageous for implementing selective etching of the implanted portion relative to the non-implanted portion. The non-implanted portion under the implanted portion can thus serve as a stop layer during etching.

[0051] In one example, ion implantation is done by an implanter.

[0052] According to one example, the ion implantation is configured such that the first P 1 and second P 2 implantation depths are less than or equal to 30 nm, preferably less than or equal to 10 nm. The ion implantation can thus be carried out on the surface of the layer. The implanted portions can serve as a braking primer or preferably as an acceleration for the etching to manufacture the patterns.

[0053] In one example, ion implantation is done by plasma.

[0054] According to one example, the implantation mask is configured such that the first and second portions are spaced apart, in a direction parallel to a main extension plane of the upper face of the layer, by a distance less than or equal to the smallest distance separating two adjacent patterns of different heights. Thus, in a direction parallel to the main extension plane of the upper face, the distance on which The resin thickness varies during pattern transfer by the mold, is less than or equal to the distance between patterns of different heights. The resin thickness only varies between two areas where the resin thickness is constant.

[0055] According to one example, the thickness gradient of the implantation mask is configured such that the first and second portions are spaced apart, in a direction parallel to the main extension plane of the upper face of the layer, by a distance less than or equal to the smallest distance separating two adjacent patterns of different heights.

[0056] According to one example, the implantation mask is configured such that the first and second portions are separated by an intermediate portion in which the implantation depth varies. The intermediate portion thus has a gradual depth gradient between the first and second portions.

[0057] In one example, the thickness gradient of the implantation mask is configured such that the first and second portions are separated by an intermediate portion in which the implantation depth varies.

[0058] According to one example, the implantation mask is configured such that the first and second portions are directly adjacent. The first and second portions thus form a steep depth gradient between P 1 and P 2 .

[0059] In one example, the thickness gradient of the implantation mask is configured such that the first and second portions are directly adjacent.

[0060] According to one example, the ion implantation is configured such that the first and second portions taken together extend substantially across the entire main extension plane of the upper face of the layer.

[0061] According to one example, prior to etching, the method comprises several ion implantations so as to implant a plurality of first portions and a plurality of second portions, the ion implantations being configured with respect to each other so that: the first portions differ from the second portions by at least one parameter taken from: a nature of the implanted ions, a dose of implanted ions, and / or the first and second portions have implantation depths P 1 , P 2 different between the first portions and the second portions.

[0062] Thus, the method makes it possible to implant first portions and second portions in the layer, preferably in a localized manner. Depending on the nature of the ion and / or the implantation depth, the etching speed is modulated to obtain patterns of different heights in each of the portions.

[0063] In one example, each implanted portion has a single implantation depth.

[0064] In one example, the implanted portions are separated from each other by the third non-implanted portion.

[0065] According to one example, at least one pattern extends in each of the implanted portions.

[0066] According to one example, at least one of the first portion and the second portion, preferably the first portion and the second portion, is / are implanted with an implantation dose substantially between 10 12< and 10 15< at / cm 2< .

[0067] According to one example, the ion implantations are configured so that each of the first and second implanted portions extends, in a direction parallel to the main direction of extension of the upper face of the layer, over a distance substantially equal to a dimension of the pattern produced during the etching, in the same direction.

[0068] According to one example, the ion implantations are performed through the etching mask such that each of the first and second implanted portions extends in line with the openings of the etching mask.

[0069] In this direction, the dimensions of an implanted portion coincide with those of the pattern to be engraved. The implanted portion thus makes it possible to modulate the properties of the layer to define the contours of the pattern during engraving.

[0070] According to one example, the etching is configured to selectively etch each implanted portion, at least the second portion and where appropriate the first and second portions, relative to the third non-implanted portion. Thus, during etching, the non-implanted portion forms an etching stop layer. The etching step is made more reliable and reproducible, by depending less and preferably no longer depending on the etching time.

[0071] In one example, the etching is configured such that the etching rate of the implanted portion is at least 100 times greater than the etching rate of the non-implanted portion.

[0072] In one example, the etching is configured so as not to etch the non-implanted portion.

[0073] In one example, the engraving is stopped after the entire thickness of the second portion located at the openings of the engraving mask has been consumed. The depth of the patterns is thus precisely controlled.

[0074] In one example, the ion implantation is configured to implant at least one of oxygen, hydrogen, helium, arsenic, phosphorus, and carbon ions into the layer.

[0075] In one example, the layer is based on or made of at least one of silicon or a material transparent to the wavelength of 365 nm.

[0076] According to one example, the process is such that H2>H1.

[0077] According to an example, the process is such H2

[0078] In one example the layer is made of silicon.

[0079] ​According to one example, the layer is based on or made of silicon oxide of formula SiO2, silicon carbide of formula SiC.

[0080] According to one example, the method comprises a single etching step.

[0081] In one example, the mold is a so-called master mold (generally referred to as master), intended to be used for the production of secondary molds for nano-printing.

[0082] According to an example, the mold is such H2>H1.

[0083] According to an example, the mold is such H2

[0084] In one example, the mold is a master mold and the total volume Vb of the recessed areas defined by the second set of patterns is greater than the total volume Va of the recessed areas defined by the first set of patterns.

[0085] ​In another example, the mold is a "direct" mold, intended to be pressed into a resin without an intermediate mold. In this case, the volume Vb of the recessed areas defined by the second set of patterns is less than the total volume Va of the recessed areas defined by the first set of patterns.

[0086] According to one example, the implantation is carried out according to a preferred implantation direction perpendicular to the upper face.

[0087] According to one example, in the mold, the first implanted portion has a first implantation depth P 1 and the second implanted portion has a second implantation depth P 2 , with P 2 strictly greater than P 1 and P 1 zero or greater than 0.

[0088] According to the invention, the layer has, in the first portion, a first set of patterns, and in the second portion a second set of patterns such as: the first set of patterns having a first density D 1 of patterns and a first height H 1 , the second set of patterns having a second density D 2 of patterns, and D 2 >D 1 , and optionally H 2 >H 1 .

[0089] According to one example, at least one, and preferably each, of the first and second implantation depths is greater than or equal to 30 nm.

[0090] According to one example, at least one, and preferably each, of the first and second implantation depths is less than or equal to 1 µm.

[0091] Preferably, at least one, and preferably each, of the first and second implantation depths is between 30 nm and 1 µm.

[0092] According to one example, the first and second implantation depths are less than or equal to 30 nm, preferably less than or equal to 10 nm.

[0093] According to one example, the first and second portions are spaced apart, in a direction parallel to the main extension plane of the upper face of the layer, by a distance less than or equal to the smallest distance separating two adjacent patterns of different heights.

[0094] It is specified that in the context of the present invention, a substrate or a layer, "based" on a species A, is understood to mean a substrate or a layer comprising this species A only or this species A and possibly other species.

[0095] A substrate comprising a layer may be: either, preferably, a stack in which the substrate comprises the layer deposited on a support layer, or a substrate comprising only the layer. In this case, the layer may be self-supporting, that is to say, it supports its own weight.

[0096] In the context of the present invention, a material which allows at least 70% of a luminous flux of this given wavelength to be transmitted is considered to be transparent to a given wavelength.

[0097] Several examples of embodiments of the invention implementing successive steps of the manufacturing process are described below. Unless explicitly stated, the adjective “successive” does not necessarily imply, even if this is generally preferred, that the steps follow one another immediately, intermediate steps being able to separate them.

[0098] Furthermore, the term "step" means the carrying out of a part of the process, and can designate a set of sub-steps.

[0099] Furthermore, the term "step" does not necessarily mean that the actions carried out during a step are simultaneous or immediately successive. Certain actions of a first step may in particular be followed by actions linked to a different step, and other actions of the first step may be repeated subsequently. Thus, the term "step" does not necessarily mean actions that are unitary and inseparable in time and in the sequence of phases of the process.

[0100] A microelectronic device is any type of device made using microelectronics. These devices include, in addition to devices for purely electronic purposes, micromechanical or electromechanical devices (MEMS, NEMS, etc.) as well as optical or optoelectronic devices (MOEMS, LEDs, etc.).

[0101] It may be a device intended to perform an electronic, optical, mechanical, etc. function. It may also be an intermediate product intended solely for the production of another microelectronic device.

[0102] It is specified that in the context of the present invention, the thickness of a layer or of the substrate is measured in a direction perpendicular to the surface along which this layer or this substrate has its maximum extension. The thickness is thus taken in a direction perpendicular to the main faces of the layer, or of the substrate on which the different layers rest. In the figures, the thickness is taken along the vertical.

[0103] It is specified that, in the context of the present invention, the terms "on", "overcomes", "covers", "underlying", "facing" and their equivalents do not necessarily mean "in contact with". Thus, for example, the deposition, transfer, assembly or application of a first layer on a second layer does not necessarily mean that the two layers are in direct contact with each other, but means that the first layer at least partially covers the second layer by being either directly in contact with it, or by being separated from it by at least one other layer or at least one other element.

[0104] A parameter that is "substantially equal to / greater than / less than" a given value means that this parameter is equal to / greater than / less than the given value, within plus or minus 10% of this value. A parameter that is "substantially between" two given values means that this parameter is at least equal to the smallest given value, within plus or minus 10% of this value, and at most equal to the largest given value, within plus or minus 10% of this value.

[0105] In the context of the present invention, a printable resin is defined as an organic or organo-mineral material that can be mechanically shaped by pressing with a mold comprising patterns. A crosslinkable or polymerizable resin is a printable resin that has the ability to crosslink or polymerize by exposure to a beam of photons, for example in the ultraviolet range and / or by applying a temperature. This type of resin is conventionally used in UV-assisted or thermally assisted nanometric printing processes.

[0106] In the context of the invention, the energies are given in electronvolts, for which 1 eV ≈ 1,602.10 -19< J, in the international system of units.

[0107] Several non-limiting examples of the invention will now be described in detail with reference to Figures 2A to 7B .

[0108] The method comprises providing a substrate 10 comprising a layer 11 having an upper face 110 and a lower face 115 opposite the upper face 110. In the figures, it is considered, without limitation, that the substrate 10 is a stack comprising a support layer 10a, which may also be referred to as a support substrate, and the layer 11 overlying the support layer 10a. It may be provided that the substrate 10 comprises only the layer 11.

[0109] The method further comprises an ion implantation configured so that the layer 11 has at least a first portion 111 and at least a second portion 112, each of these portions extending from the upper face 110. The properties of these portions are different from each other, so that an etching of patterns 114a, 114b from each of these portions 111, 112 gives patterns 114a, 114b of different heights.

[0110] For this, the ion implantation is configured so that the first portion 111 is not implanted or has a first implantation different from the second implantation. The second portion 112 is implanted, and has the second implantation. According to one example, the first implantation and the second implantation differ by, as described later in more detail with reference to the figures: an implantation depth, and / or a nature of the implanted ions, and / or an implanted ion dose.

[0111] For this, the ion implantation parameters can be varied, and for example the type of ions implanted, the implantation energy and / or the dose of ions implanted, in a manner known to the person skilled in the art. In practice, ion implantation induces in the implanted material a lateral extension of the implanted zone due to the interactions (elastic and inelastic) between the ions and the implanted material, which results in the presence of a diffusion bulb for the implanted ions, well known to the person skilled in the art. The geometric shape of this bulb, namely the implanted depth and any lateral extensions of the latter, depends in particular on: implantation conditions: atomic number of the implanted ion and the acceleration voltage in the equipment; materials of the deposited layers and the substrate used which will impact the intensities of the interactions between the ions and the implanted materials.

[0112] The person skilled in the art may, for example, use known tools such as SRIM (abbreviated from the English Stopping and Range of Ions in Matter, which can be translated as "stopping and carrying of ions in matter") or TRIM (abbreviated from English Transportation of Ions in Matter, which can be translated as “transport of ions in matter”) which allow the simulation of interactions between ions and the material of layer 11.

[0113] The ion implantation further defines in the layer 11 a third non-implanted portion 113 extending at least from the first portion 111, and preferably from the first 111 and second 112 portions to the lower face 115 of the layer 11. The third portion 113 extends more particularly in line with the first portion 111 only, or in line with the first 111 and second 112 portions. According to one example, the second portion 112 extends to the lower face 150 of the layer 11.

[0114] Before or after implantation, an etching mask 13 is produced on the upper face 110. The etching mask 13 has a plurality of openings 130a, 130b from which the patterns of the mold 1 will be formed in the etching step.

[0115] After the production of the etching mask 13 and after the implantation, the method further comprises an etching of the layer 11 configured so as to have a different etching speed between at least the second portion 112 and the third portion 113. The etching may be a wet etching or preferably a dry etching, for example a plasma etching or a reactive ion etching (commonly abbreviated RIE, from the English " Reative Ion Etching ").

[0116] According to one example, the etching of the layer 11 is configured so as to have a different etching speed between the assembly formed by the first 111 and second 112 portions, and the third portion 113. According to another example, the etching of the layer 11 is configured so as to have a different etching speed between each of the first portion 111, the second portion 112 and the third portion 113.

[0117] The etching is configured to form at least one pattern 114a extending in the first portion 111 and at least one pattern 114b extending in the second portion 112, from the upper face 110. The patterns 114a, 114b may extend only in the first portion 111 and / or second portion 112. The patterns 114a, 114b may extend respectively in the first 111 and second portion 112, and in the third portion 113 extending between the first 111 and / or second portion 112 and the lower face 150 of the layer 11. The patterns are hollow shapes preferably extending in line with the upper face 110, from this face 110, etched through the openings 130a, 130b of the etching mask 13. The patterns are formed in line with the upper face 110, from this face 110, etched through the openings 130a, 130b of the etching mask 13. walls delimited by the openings 130b, 130b of the etching mask 13.

[0118] The different etching speeds make it possible to etch different patterns between the first 111 and second 112 portions, and more particularly patterns of different heights in the layer 11, the height being taken from the upper face 110, or equivalently from the tops of the patterns 114a, 114b, to the bottom of the patterns, in a direction perpendicular to the main extension plane of the upper face 110. In the figures, the height of the patterns is taken along the vertical.

[0119] According to a preferred example, the etching speed of the second portion 112 is strictly greater than the etching speed of a non-implanted portion of the layer 11, and in particular the third portion 113. A non-implanted portion thus forms a braking layer, or even a stopping layer, for the etching, making it possible to better control the height of the etched patterns 114a, 114b. According to one example, the etching speed of the assembly formed by the first 111 and second 112 portions is strictly greater than the etching speed of the third portion 113. According to another example, the etching speed of each of the first portion 111 and the second portion 112 is strictly greater than the etching speed of the non-implanted third portion 113, the etching speeds between the first portion 111 and the second portion 112 possibly differing.

[0120] According to an example, it is sought to etch a first set of patterns 114a having a first density, and a second set of patterns 114b having a second density. In the context of this invention, the term "density" denotes the surface or volume occupied by the hollow shapes that constitute the patterns 114a, 114b in the layer 11, on a given surface taken along a section of the patterns parallel to the upper face 110 or the lower face of the layer 11. A low density corresponds to a set of patterns having a small hollow volume on the given surface. A high density corresponds to a set of patterns having a large hollow volume on a surface of the same dimension. For example, as illustrated by the Figures 4C , 5C And 6D : compact patterns have a high density, and are therefore spaced by a smaller distance L b, spaced patterns have a low density, and are therefore spaced by a larger distance L a.

[0121] Note that density here refers to an average density over a given surface. Variations between the distances L a and / or L b can be observed within the same set of patterns. L a does not vary by more than 20% between the patterns 114a for the first set. L b does not vary by more than 20% between the patterns 114b for the second set.

[0122] When transferring the reliefs from mold 1 into the layer to be printed to form the patterns, in order to obtain a more homogeneous residual thickness of resin between the sets of patterns of different densities, the height between the sets of patterns can be varied.

[0123] According to the invention, the implantation of the first 111 and second 112 portions and the etching are configured so that: the first set of patterns 114a has a first density D 1 of patterns and a first height H 1 , the second set of patterns 114b has a second density D 2 of patterns, and a second height H 2 , with D 2 >D 1 , and optionally H 2 >H 1 .

[0124] H 1 and H 2 each denote an average pattern height for the corresponding set. H 1 does not vary by more than 20% between patterns 114a for the first set. H 2 does not vary by more than 20% between patterns 114b for the second set.

[0125] For this, the first set of patterns 114a can be etched in the first portion(s) 111, and the second set of patterns 114b can be etched in the second portion(s) 112. The difference in etching speed described above thus makes it possible to adapt the height of the patterns according to the density of the sets of patterns and thus to further improve the homogeneity of the residual resin layer during nano-printing with the mold 1.

[0126] For example, in the case where the patterns 114a, 114b are networks of lines, the residual thickness H of resin after printing by the mold, for example the master mold or a secondary mold made from a master mold, can be expressed as follows: H résiduelle = H initiale − H moule n / 1 + L / S With : L the width of the lines on the mold, S the width of the spaces on the mold, Hmoule(n) the depth of the patterns n of the mold, Hinitiale the initial resin thickness.

[0127] For two different pattern densities D 1 , D 2 , the L / S ratio is different. In order to obtain the same residual thickness H of resin after printing by the mold, the mold must have two different pattern heights H mold(1) , H mold(2) . The process is therefore implemented so that E 1 corresponds to H mold(1) , and E 2 corresponds to H mold(2) .

[0128] Each pattern 114a, 114b further has a pattern volume corresponding to the volume of the recessed area defined by the patterns 111a, 114b in question in the layer 11. Each set of patterns 114a, 114b has a total volume Va, Vb respectively, corresponding to the sum of the pattern recessed volumes of the patterns 114a, 114b constituting it. The total volume Va, Vb depends on the height H1, H2 and the density D1, D2 of the patterns 114a, 114b. Increasing the height H1, H2 or the density D1, D2 of the patterns 114a, 114b has the consequence of increasing the volume Va, Vb of the sets of patterns 114a, 114b.

[0129] During the nanoimprinting step, the volume of resin that can be accommodated by a set of patterns 114a, 114b is equal to the total volume Va, Vb of the latter. Thus, for the thickness of the residual layer to be homogeneous, the ratio Va / Vb between the total volumes Va, Vb must be correctly defined, and in particular it must be judiciously chosen if Va>Vb or if Va <Vb. L'implantation des première 111 et deuxième 112 portions et la gravure sont configurées pour que les valeurs de ces volumes totaux Va, Vb soient telles que la résine se répartisse de façon satisfaisante entre les différents ensembles de motifs 114a, 114b. Naturellement, le dimensionnement de Va et de Vb devra prendre en compte si le moule fabriqué est destiné à être utilisé pour la fabrication d'un moule secondaire, ou s'il est destiné à imprimer directement une résine.

[0130] Following the etching, the method may comprise removing the etching mask 13 to obtain the mold 1. The method may comprise, before removing the etching mask 13, a preliminary heat treatment step for compatibility of the materials with the removal step.

[0131] It is therefore understood that the mold 1 comprises in the layer 11 carrying the patterns 114a, 114b intended to be printed in a layer to be structured on a separate substrate, at least a first portion 111 not implanted or having a first implantation, and at least a second portion 112 having a second implantation different from the first implantation. The first 111 and second 112 portions each extend from said upper face 110. The layer further comprises a third non-implanted portion 113 extending at least from the first portion 111, and preferably from the first 111 and second 112 portions, to the lower face 115 of the layer 10. The characteristics are described relative to the method of manufacturing the mold. These characteristics can be entirely transposed to the mold 1.

[0132] Preferably, the mold 1 is a master mold intended to carry out nano-printing of patterns by indirect replication. However, it may be provided that the mold 1 is used for nano-printing by direct replication.

[0133] The ion implantation may be configured to implant at least one of oxygen, hydrogen, helium, arsenic, phosphorus, zinc, and carbon ions into layer 11. The ion implantation of these ions, as well as the parameters for this, is known to those skilled in the art. For example, reference may be made to Figures 7A and 7B, represent ion implantation diagrams respectively in silica SiO 2 and in a photoresist, available in the literature for many ions and different materials. These diagrams represent in solid lines the distance traveled 5 (in angstrom Å 10 -10< m) in the material by the ions, according to the implantation energy 6 (in keV, i.e. 10 3< eV), with in dotted lines the distribution range of the distance traveled by the ions during implantation 7 (commonly designated by the symbol σ), according to the implantation energy 6 (in keV, i.e. 10 3< eV). In Figure 7A , the ions shown are boron B, phosphorus P and arsenic As. In Figure 7B , the ions illustrated are boron B, silicon Si, hydrogen H and phosphorus P ions. The person skilled in the art, upon reading such diagrams, will know which parameters and in particular which implantation energy to use to adapt the depths P 1 and P 2 .

[0134] According to one example, the layer 11 is based on or made of silicon and / or a material transparent to the wavelength of 365 nm. According to one example, the layer is made of silicon. Concerning the materials transparent to the wavelength of 365 nm, according to one example, the layer is based on or made of silicon oxide of formula SiO 2 , silicon carbide of formula SiC, preferably the layer then has a thickness less than or equal to 100 µm. According to another example, the layer is based on or made of silicon nitride of formula Si 3 N 4 , preferably the layer then has a thickness less than or equal to 10 nm.

[0135] The implantation mask 12 may be based on or made of a lithography resin. The implantation mask may comprise an underlayer at the interface between the resin and the upper face 110, called a partial transmission mask based on or made of titanium nitride of formula TiN or silicon nitride of formula Si 3 N 4 . The etching mask 13 may be based on or made of the same materials as the implantation mask 12. Specific examples of implementation of the process

[0136] Particular examples of carrying out the method are now described.

[0137] According to an example illustrated by the Figures 2A to 5C , the method may comprise producing an implantation mask 12 on at least a portion 110a of the upper face 110 of the layer 11. As illustrated for example by the Figures 2A and 2B, the production of the implantation mask 12 can be configured so that the implantation mask 12 has a thickness gradient between at least a first thickness E 1 and a second thickness E 2 , with E 1 strictly greater than E 2 and E 2 zero or strictly greater than 0. The implantation mask 12 thus creates a thickness differential above the layer 11. In the Figures 2A and 2B , we illustrate, without limitation, the example according to which the thickness E 2 is non-zero.

[0138] The ion implantation can be carried out through the implantation mask 12. Thanks to the thickness differential of the implantation mask 12, the first implanted portion 111 can have a first implantation depth P 1 and the second implanted portion 112 can have a second implantation depth P 2 , with P 2 strictly greater than P 1 and P 1 zero or greater than 0. The path of the ions is considered in a preferred direction perpendicular to the main extension plane of the upper face 110 of the layer 11.

[0139] According to the example illustrated by the Figures 3A and 3B, we have P 2 > P 1 > 0. Thus, the first portion 111 is implanted up to the first depth P 1 , and the second portion 112 is implanted up to the second depth P 2 . The third portion 113 can extend from the first depth P 1 , and preferably from the first and second depths P 1 , P 2 , up to the lower face 150 of the layer 11. According to one example, the entire upper face 110 of the layer 11 is implanted, at different depths.

[0140] For this, the ion implantation can be configured to implant the layer 11 through the implantation mask 12 so that the implanted ions pass through the implantation mask 12 and penetrate into the layer 11, over a distance greater than E 1 and E 2 taken perpendicular to the upper face 110 of the layer 11.

[0141] The ion implantation may for this purpose be configured so that at least one, and preferably each, of the first P 1 and second P 2 implantation depths is greater than 30 nm, and preferably less than 1 µm. The distance traveled by the ions following their penetration into the implantation mask 12 may be greater than 30 nm, and preferably less than 1 µm. The ion implantation may more particularly be carried out by an implanter device, in a manner known to those skilled in the art.

[0142] According to the example illustrated by the Figure 3C, we have P 2 > P 1 and P 1 = 0 relative to the level of the upper face 110 of the layer 11. Thus, the first portion 111 has a zero implantation depth P 1 at the level of the layer 11. The first portion 111 is therefore not implanted in the layer 11 and can be confused with the third non-implanted portion 113. The second portion 112 is implanted up to the second non-zero depth P 2, in the layer 11. The third portion 113 can extend from the second depth P 2 , up to the lower face 150 of the layer 11. Thus, a fraction of the upper face 110 is not implanted.

[0143] For this, the ion implantation can be configured to implant the layer 11 through the implantation mask 12 so that the implanted ions pass through the implantation mask 12 over a distance less than E 1 and do not penetrate into the layer 11 at the first portion 111. According to this example, the implanted ions pass through the implantation mask 12 over a distance greater than E 2 and penetrate into the layer 11 at the second portion 112.

[0144] The ion implantation can therefore be configured so that the first P 1 and second P 2 implantation depths are less than 30 nm, preferably less than 10 nm. The distance traveled by the ions following their penetration into the implantation mask 12 can be less than 30 nm, preferably less than 10 nm. The ion implantation can more particularly be carried out by a plasma, and in particular by immersing the substrate 10 in a plasma, in a manner known to those skilled in the art.

[0145] According to one example, the first thickness E 1 is substantially between 50 nm and 100 µm. According to one example, the second thickness E 2 is substantially between 0 nm and E1. These dimensions are notably chosen according to the design of the mold and the intended application. According to one example, the thickness gradient of the mask is substantially equal to the difference in depth between P 1 and P 2 .

[0146] The implantation mask 12, to present this thickness gradient, can for example be produced by grayscale lithography, or alternative methods such as near-field lithography, for example by the NanoFrazor ™ equipment and the associated method. The choice of the appropriate technology will depend on the tolerances on the distance L 0 which separates sets of patterns of different heights, in a direction parallel to the main extension plane of the upper face 110.

[0147] According to one example, the implantation mask 12 is configured so that the first 111 and second 112 portions are spaced apart, in a direction parallel to the main extension plane of the upper face 110, by a distance L 0 less than the smallest distance L 1 separating two adjacent patterns 114a, 114b of different heights, and more particularly separating a first set of patterns 114a and a second set of patterns 114b, as illustrated in Figures 3A to 3C in comparison with the Figures 4C And 5C .

[0148] As illustrated by the Figure 3B, the implantation mask 12 may have a progressive thickness gradient between E 1 and E 2 , over the length L 0 . Note that E 2 may be zero, the implantation mask 12 covering only a fraction 110a of the upper face 110, or be strictly greater than 0. Following the ion implantation, the first 111 and second 112 portions may thus be separated by an intermediate portion 116, in a direction parallel to the main extension plane of the upper face 110. In this intermediate portion 116, the implantation depth may vary between P 1 and P 2 to form a progressive depth gradient. Note that it may be provided that P 1 is zero, or strictly greater than 0 as illustrated, according to the examples described previously. Preferably L 0 is substantially less than or equal to the smallest distance separating the first and second portions. As illustrated by the Figures 3A and 3C, the implantation mask 12 may have a steep thickness gradient between E 1 and E 2 , over a length L 0 for example substantially less than or equal to the smallest distance separating the first and second portions. Note that, here again, E 2 may be zero or strictly greater than 0. Following the ion implantation, the first 111 and second 112 portions may thus be directly adjacent in a direction parallel to the main extension plane of the upper face 110.

[0149] According to one example, the method comprises removing the implantation mask 12 after the implantation and before the etching step, preferably before producing the etching mask 13.

[0150] According to one example, the etching mask 13 is produced after the ion implantation, as illustrated for example by the passage of the Figures 3A and 3C to Figures 4A And 5A. During etching, the implanted portions of layer 11 preferably have a higher etching rate than the non-implanted portions.

[0151] As illustrated for example by the Figures 4A And 5A , the etching mask 13 may have openings 130a and 130b delimiting openings corresponding to the patterns 114a and 114b to be etched in the layer 11. A distance L 1 may separate the set of patterns 114a and the set of patterns 114b, of different pattern densities, for example symbolized by the lengths L a and L b . The difference in etching speed between the implanted portions and the non-implanted portions results in the etching of patterns 114a, 114b of different heights, as illustrated by the Figures 4B And 5B . Following the etching, the method may include removing the etching mask 13, to obtain the mold 1 illustrated by the Figures 4C And 5C

[0152] An example of engraving is now described with reference to the Figures 4A to 4C The etching can be carried out over an etching time chosen so that the entire thickness of the second portion 112 is consumed at the openings 130b of the etching mask 13, preferably without consuming the third portion 113. The first portion 111 having a depth P 1 less than the depth P 2 of the second portion 112, and the third portion 113 having a lower etching speed, the height of the patterns 114a will be less than the height of the patterns 114b in the second portion 112. The depth of the patterns is thus precisely controlled with the etching time.

[0153] According to one example, the etching is configured to selectively etch each implanted portion relative to the third non-implanted portion 113. The etching may be configured such that the entire thickness of the first 111 and second 112 portions is consumed at the openings 130b of the etching mask 13. Thus, the non-implanted portion 113 forms a stop layer for the etching. Only the first 111 and second 112 portions are significantly etched, which allows a controlled stop of the etching. Control of the depth of the patterns 114a, 114b is thus further improved.

[0154] An example of engraving is now described with reference to the Figures 5A to 5CThe second portion 112 may have an etching speed greater than that of the third portion 113. The etching may be carried out over an etching time chosen so that the entire thickness of the second portion 112 is consumed at the openings 130b of the etching mask 13, as well as a portion of the third portion 113. The second portion 112 being consumed more quickly, a height differential may be obtained between the patterns 114a of height H 1 and the patterns 114b of height H 2 for the same etching time, as illustrated by the Figure 5B Note that it can be provided that the second portion 112 has a lower engraving speed than that of the third portion 113, the height differential then being reversed.

[0155] Another example of carrying out the method is now described with reference to Figures 6A to 6DThe method may comprise several ion implantations so as to implant a plurality of first portions 111 and a plurality of second portions 112. Each implanted portion may be separated from the adjacent implanted portion by a third non-implanted portion 113. The ion implantations are thus carried out in a localized manner in the layer 11.

[0156] For this, the method may comprise producing the etching mask 13, the etching mask having the openings 130a, 130b corresponding to the patterns 114a, 114b to be etched. The ion implantation may be carried out through the etching mask 13 and be configured so that the implanted portions 111, 112 extend in the layer 11 in line with the openings 130a, 130b. Each of the first and second implanted portions 111, 112 may extend, in a direction parallel to the main direction of extension of the upper face 110, over a distance L 3 , L 4 substantially equal to a dimension L 3 , L 4 of the corresponding pattern 114a, 114b produced during the etching, in the same direction. The lengths L 3 , L 4 are preferably substantially equal to the distance between the walls delimiting the openings 130a, 130b, in this direction.

[0157] The ion implantations can be configured with each other so that the first portions 111 differ from the second portions 112 by: their implantation depths P 1 , P 2 , as for example illustrated by the Figure 6A , and / or a nature of the implanted ions, and / or a dose of implanted ions, as for example illustrated by the Figure 6B .

[0158] The first portions 111 may correspond to the first set of patterns 114a described previously. The second portions 112 may correspond to the second set of patterns 114b described previously.

[0159] Ion implantations can be performed by an implanter. The implanter may include blades 4 (commonly referred to as "blades"). blade") movable so as to mask a part of the etching mask 13. During a first ion implantation, the blade 4 can mask the openings 130b so as to implant only the first portions 111. During a second ion implantation, the blade 4 can mask the openings 130a so as to implant only the second portions 112. Thus, the portions 111, 112 can be successively implanted without requiring multiple steps of depositing an etching mask 13 and implantations for each type of implanted portions.

[0160] As illustrated by the Figure 6A, the first portions 111 may differ from the second portions 112 by their implantation depth, with P1 < P2. The etching may be carried out over an etching duration chosen so that the entire thickness of the second portions 112 is consumed at the openings 130b of the etching mask 13, preferably without consuming the third portion 113. The first portions 111 having a depth P1 less than the depth P2 of the second portion 112, the height of the patterns 114a will be less than the height of the patterns 114b in the second portions 112. The depth of the patterns is thus precisely controlled with the etching time.

[0161] According to a preferred example, the etching is configured to selectively etch each implanted portion 111, 112 with respect to the third non-implanted portion 113. The etching may be configured so that the entire thickness of the first 111 and second 112 portions 11 is consumed at the openings 130b of the etching mask 13. Thus, the non-implanted portion 113 forms a stop layer for the etching. Only the first 111 and second 112 portions are significantly etched, which allows a controlled stop of the etching. This may, as an example, be illustrated by the passage of the Figure 6A to the Figure 6C . The depth control of patterns 114a, 114b is thus further improved.

[0162] As illustrated by the Figure 6B, the first portions 111 may differ from the second portions 112 by the nature of the implanted ions and / or the implanted dose, for the same depth P1 as illustrated or different implantation depths. The etching may be carried out over an etching time chosen so that the entire thickness of the second portions 112 is consumed at the openings 130b of the etching mask 13, and consume at least a part of the third portion 113. The first portions 111 may have an etching speed lower than that of the second portions 112. The second portions 112 being consumed more quickly, a height differential may be obtained between the patterns 114a of height H 1 and the patterns 114b of height H 2 for the same etching time, as illustrated by the passage of the Figure 6B to the Figure 6C. Note that it can be provided that the second portions 112 have a lower engraving speed than that of the first portions 111, the height differential then being reversed.

[0163] As indicated above and illustrated by the passage from the Figure 6C to the Figure 6D , the etching mask 13 can be removed after the patterns 114a and 114b have been produced.

[0164] There Figure 6D illustrates in particular a mold 1 intended to serve as a master mold in a nano-imprinting process. As illustrated in Figure 6E , it can in fact be used to make a secondary mold 200 presenting inverse patterns, which will be printed in the resin to be structured. On the Figure 6E, the master mold 1 is shown under the secondary mold 200 for the sake of clarity and consistency with the previous figures. Naturally, in the context of the production of the secondary mold 200, during the pressing step, the master mold 1 may be placed above a deformable layer intended to form the secondary mold 200 and pressed into the latter. In this application, the dimensions of the openings 130a in the etching mask and the implantation parameters in particular will be chosen such that the total volume Vb of the recessed areas defined by the second set of patterns 114b is greater than the total volume Va of the recessed areas defined by the first set of patterns 114a. Va being the surface area occupied by the recesses of the patterns 114a of the first set, surface area taken in a horizontal plane on the Figures 6A to 6E , and Vb being the surface occupied by the hollows of the patterns 114b of the second set, surface taken in a horizontal plane on the Figures 6A to 6E. According to the invention, the density of the second set of patterns 114b is such that D2>D1, with the condition on the height of the patterns preferably H2>H1 or H2 <h1 tant que vb>Va. It may also be provided, according to a variant not forming part of the invention, that D2<D1 et H2> H1 as long as Vb>Va. The dimensions D1, D2, H1 and H2 being taken from the master mold 1. In this way, as shown in Figure 6F , during the nano-printing of the secondary mold 200 in a layer of resin, the resin is distributed in such a way that the residual layer 30' has a homogeneous thickness. This makes it possible to maintain the critical dimensions of the patterns 31a', 31b' during their etching in the substrate 3', or at least to limit their degradation ( figure 6G ).

[0165] The manufacturing method can also be implemented with a view to manufacturing a so-called direct mold, i.e. intended for direct replication of the patterns, without going through a master mold and then a secondary mold. In this case, the dimensions of the openings 130a in the etching mask and the implantation parameters in particular will this time be chosen such that the total volume Vb of the recessed areas defined by the second set of patterns 114b is less than the total volume of the recessed areas Va defined by the first set of patterns 114a. For this, it is possible to have, according to a variant not forming part of the invention, D2 <D1 avec comme condition sur la hauteur des motifs H2<H1. On peut également avoir, selon une variante ne faisant pas partie de l'invention, D2<D1 et H2> H1 as long as Vb<Va. On peut également prévoir que D2> D1 according to the invention, and H2 <H1 tant que Vb<Va.The dimensions D1, D2, H1 and H2 being taken from the single “direct” mold, as illustrated in . figure 8A . In this way, we again obtain a better distribution of the resin and therefore a residual layer 30' of homogeneous thickness during nano-printing ( figure 8B ). As previously, the critical dimensions of the patterns 31a', 31b' are preserved or, at least, less degraded than in state-of-the-art processes ( figure 8C ). Particular example of implementation of the process by a user

[0166] Below we describe an example of implementation of the process by a user, without limitation. the user chooses the material to be implanted, depending on the material chosen, the user selects ions to be implanted, which: o modify the previously chosen material to be implanted, and o make it possible to identify an etching chemistry (dry or wet) to selectively etch the implanted portion(s) of the non-implanted material.Experimental tests on full wafers (wafers without or with pattern) can be implemented to identify the optimal etching process(es), the implantation conditions are then determined by simulation according to the desired geometries (for example depth of the patterns), knowing the ions and the implantation conditions we can then identify materials which will serve as mask and protection for the implantations, in particular materials with sufficient stopping power, the deposition of the mask and the ion implantation are then carried out, the mask can be removed or kept for later removal, selective etching is implemented to form the patterns, if the dimensions of the patterns differ from the targeted dimensions then a correction on the patterns can be carried out to adjust these dimensions, for example by optical proximity correction (commonly abbreviated OPC, from the English . optical proximity correction).

[0167] In view of the foregoing description, it is clear that the invention provides a manufacturing method for improving the manufacturing of a mold for nano-imprinting to control the residual thickness of resin, as well as a mold improving the control of the residual thickness of resin.< / h1>

Claims

1. Method for manufacturing a mould (1) for nanoprinting, comprising: • a provision of a substrate (10) comprising a layer (11) having an upper face (110) and a lower face (115) opposite the upper face (110), • at least one ion implantation in at least one portion of the layer (11), the ion implantation being configured, so as to obtain within the layer (11) at least one first non-implanted portion (111) or having a first implantation, and at least one second portion (112) having a second implantation, the first implantation and the second implantation being different, the first (111) and second (112) portions each extending from said upper face (110), the ion implantation further defining a third non-implanted portion (113), extending at least from the first portion (111), to the lower face (115) of the layer (10), • after or before implantation, the production of a so-called etching mask (13), surmounting the upper face (110) and having a plurality of openings (130a, 130b), • after implantation, an etching of the layer (10) configured so as to have a different etching speed at least between the second portion (112) and the third portion (113), so as to etch through the openings (130a, 130b) of the etching mask (13), a plurality of patterns (114a, 114b) of different heights in the layer, at least one pattern (114a) extending into the first portion (111) and at least one pattern (114b) extending into the second portion (112), the etching being configured to etch in the first portion (111), a first set of patterns (114a) and to etch in the second portion (112), a second set of patterns (114b): i. the first set of patterns (114a) having a first pattern density D1 and a first height H1, ii. the second set of patterns (114b) having a second pattern density D2, and a second height H2, and wherein D2>D1, preferably the first implantation and the second implantation differ by at least one parameter from among: an implantation depth, a nature of the implanted ions, a dose of implanted ions.

2. Method according to any one of the preceding claims, wherein the etching is configured such that the etching speed at least of the second portion (112), is greater than the etching speed of the third non-implanted portion (113).

3. Method according to any one of the preceding claims, wherein, prior to the ion implantation, the method comprises the production of a so-called implantation mask (12) on at least one portion (110a) of the upper face (110) of the layer (11), and the ion implantation is at least partially performed through the implantation mask (12), such that the first implanted portion (111) has a first implantation depth P1 and the second implanted portion (112) has a second implantation depth P2, with P2 strictly greater than P1 and P1 zero or greater than 0, preferably the implantation mask (12) is configured so as to have a thickness gradient between at least one first thickness E1 and one second thickness E2, with E1 strictly greater than E2 and E2 zero or greater than 0.

4. Method according to the preceding claim, wherein the ion implantation is configured, such that at least the second implantation depth P2 is greater than 30nm.

5. Method according to claim 3, wherein the ion implantation is configured, such that the first P1 and second P2 implantation depths are less than or equal to 30nm, preferably less than or equal to 10nm.

6. Method according to any one of the three preceding claims, wherein the implantation mask (12) is configured such that the first (111) and second (112) portions are spaced apart, in a direction parallel to a main extension plane of the upper face (110) of the layer (11), by a distance (L0) less than the smallest distance (L1) separating two adjacent patterns (114a, 114b) of different heights.

7. Method according to any one of the four preceding claims, wherein the implantation mask (12) is configured, such that the first (111) and second (112) portions are separated by an intermediate portion (116), wherein the implantation depth varies, or the implantation mask (12) is configured, such that the first (111) and second (112) portions are directly adjacent.

8. Method according to any one of claims 1 and 2, wherein, prior to the etching, the method comprises several ion implantations, so as to implant a plurality of first portions (111) and a plurality of second portions (112), the ion implantations being configured together, such that: • the first portions (111) differ from the second portions (112) by at least one parameter taken from among: a nature of the implanted ions, a dose of implanted ions, and / or • the first and second portions (111, 112) have different implantation depths P1, P2 between the first portions (111) and the second portions (112), preferably the ion implantations are performed through the etching mask (13), such that each of the first and second implanted portions (111, 112) extends in line with the openings (130a, 130b) of the etching mask (13).

9. Method according to any one of claims 1 to 4 and 6 to 8, wherein the etching is configured to selectively etch each implanted portion (111, 112) with respect to the third non-implanted portion (113).

10. Method according to any one of claims 1 to 4 and 6 to 9, wherein the etching is stopped after having consumed the entire thickness of the second portion (112) located in line with the openings (130b) of the etching mask (13).

11. Method according to any one of the preceding claims, wherein the ion implantation is configured to implant at least one from among oxygen, hydrogen, helium, arsenic, phosphor and carbon ions, in the layer (11).

12. Method according to any one of the preceding claims, wherein the layer (11) is with the basis of at least one from among silicon or a transparent material with a 365nm wavelength.

13. Method according to any one of the preceding claims, wherein H2>H1 or H2<H1.

14. Mould (1) for nanoprinting, comprising: • a substrate (10) comprising a layer (11) having an upper face (110) and a lower face (115) opposite the upper face (110) and several patterns (114a, 114b) extending from the upper face (110), the layer (11) being intended to penetrate into a layer to be printed to transfer the patterns (114a, 114b) there, at least one of the patterns (114a) having a height different from another pattern (114b), characterised in that the layer (11) comprises at least one first non-implanted portion (111) or portion having a first implantation, and at least one second portion (112) having a second implantation, the first implantation and the second implantation being different, the first (111) and second (112) portions each extending from said upper face (110), and a third non-implanted portion (113), extending at least from the first portion (111), to the lower face (115) of the layer (10), a first set of patterns (114a) extending into the first portion (111) and a second set of patterns (114b) extending into the second portion (112), with: i. the first set of patterns (114a) having a first pattern density D1 and a first height H1, ii. the second set of patterns (114b) having a second pattern density D2, and a second height H2, and wherein D2>D1, preferably the mould is a so-called master mould, intended to serve for the production of secondary moulds for nanoprinting, and H2>H1, or, the mould is a so-called direct mould, intended to serve the nanoprinting, and H2<H1.

15. Mould (1) according to the preceding claim, wherein the first implanted portion (111) has a first implantation depth P1 and the second implanted portion (112) has a second implantation depth P2, with P2 strictly greater than P1 and P1 zero or greater than 0, preferably the first (111) and second (112) portions are spaced apart, in a direction parallel to the main extension plane of the upper face (110) of the layer (11), by a distance (L0) less than the smallest distance (L1) separating two adjacent patterns (114a, 114b) of different heights.