The present invention relates to the field of nanostructured block copolymers having nanodomains oriented in a particular direction.

More specifically, the present invention relates to a block copolymer film that includes at least one amorphous block that can be easily eliminated after structuring and has a high phase separation with a small L ₀ period, preferably below 20 nm.

The term "period", represented by L ₀ in the rest of the description of this specification, is intended to indicate the minimum distance between two adjacent regions having the same chemical composition separated by regions having different chemical compositions.

The development of nanotechnology has enabled continuous miniaturization of products, especially in the field of microelectronics and microelectromechanical systems (MEMS). At present, as traditional lithography technology cannot manufacture structures with dimensions below 60 nm, traditional lithography technology can no longer meet these continuous demands for miniaturization.

Therefore, it is necessary to adapt the lithography technology and create an etching resist that can be created at a higher resolution with smaller and smaller patterns. The use of block copolymers can be constructed by phase separation between the blocks (also translated as structured in this article) to form the arrangement of the constituent blocks of the copolymer, thereby forming at a size below about 50nm. Nano area. Because of this ability to be structured by nanometers, the use of block copolymers in the electronics or optoelectronics fields is now widely known.

Among nanolithography resists, the most widely studied block copolymer film to date is based on polystyrene- b -poly (methyl methacrylate), which is hereinafter referred to as PS- b- PMMA. membrane. Accordingly, the paper entitled "Directed self-assembly of block copolymers for nanolithography: fabrication of isolated features and essential integrated circuit geometries", ACSNano 2007, 1, 168, MP Stoykovich et al. An advanced lithography method based on assembly and using PS-b-PMMA (polystyrene- b -poly (methyl methacrylate)) resist. In order to be able to use this block copolymer film as an etching resist, one block of the copolymer must be selectively removed to create a porous film of residual blocks, and then its pattern can be transferred to the underlying layer by etching. Regarding PS- b- PMMA films, PMMA (poly (methyl methacrylate)) is usually selectively removed to create a residual PS (polystyrene) resist. To create this resist, the nano area must be oriented perpendicular to the surface of the underlying layer. This structuring of these regions requires special conditions, such as the preparation of the surface of the underlying layer, and the composition of the block copolymer. An important factor is the phase separation factor, also known as the Flory-Huggins interaction parameter and expressed as "χ". In particular, this parameter allows it to control the size of the nano area. More specifically, it defines the tendency of the blocks of the block copolymer to separate into nanometer regions. Therefore, the product χN of the Flory-Huggins parameter χ and the degree of polymerization N is an indicator of the compatibility of the two blocks and whether they are separated at a specified temperature. For example, if the product χN is greater than 10.49, the diblock copolymer with a completely symmetrical composition is separated into micron regions. If this product χN is less than 10.49, the blocks are mixed together and phase separation cannot be observed at the observation temperature.

Because of the ongoing demand for miniaturization, it is often sought to increase the degree of phase separation in order to produce extremely high resolutions (generally below 20 nm, and preferably below 15 nm) while retaining certain basic properties of the block copolymer ( For example, the block copolymer has good temperature resistance, or when the block copolymer is PS- b- PMMA, the depolymerization of PMMA under UV treatment, etc.).

In Macromolecules, 2008, 41, 9948, Y. Zhao et al. Estimated the Flory-Huggins parameters of PS- b- PMMA block copolymers. The Flory-Huggins parameter χ follows the following equation: χ = a + b / T, where a and b values are constant specific values depending on the block nature of the copolymer and T is applied to the block copolymer to enable it to organize In order to obtain the phase separation of the region, the orientation of the region and the number of defects are reduced in order to obtain the heat treatment temperature of the region itself. More specifically, the a and b values represent the contributions of entropy and enthalpy, respectively. Therefore, for PS- b- PMMA block copolymers, the phase separation factor obeys the following equation: χ = 0.0282 + 4.46 / T.

This low value of the Flory-Huggins interaction parameter χ (0.04 at 298K) therefore limits the advantages of PS and PMMA-based block copolymers in fabricating structures with extremely high resolution.

To overcome this problem, MD Rodwing et al. Have shown in a paper entitled "Polylactide-poly (dimethylsiloxane) -Polylactide triblock copolymer as multifuntional materials for nanolithographic application," ACSNano 2010, 4, 725, that the two copolymers can be changed. The chemical nature of the block is to improve the Flory-Huggins parameter χ and the desired morphology with a manufacturing cycle below 20nm. This result has been obtained with poly (lactic-b-dimethylsilane- b -lactic acid) PLA- b- PDMS- b- PLA copolymer.

However, H. Takahashi et al. Also confirmed in the paper entitled "Defectivity in laterally confined lamella-forming diblock copolyme: thermodynamic and kinetic aspects," Macromolecules 2012, 45, 6253 that the Flory-Hugginsχ parameter can affect the dynamics of separation and This has an impact on the drive to reduce defects. When the area is organized, the separation force caused by the high value of the Flory-Huggins χ parameter is slowed down, causing the appearance of defects.

Therefore, research has shifted to other block copolymers, especially block copolymers that combine polyester-type blocks with blocks of different nature (for example, polyether or polyolefin-type). The development of selective polymerization processes with controlled and active properties allows the preparation of block copolymers containing blocks of altered chemical nature and well-defined structures. Among some of these polymers, the compatibility of the blocks is low, which leads to separation and nanostructure. The chemical nature of the blocks studied is very diverse and in recent years more attention has been paid to incorporating biodegradable blocks (especially polyester types, which can be easily eliminated after nanostructured). PLA (polylactic acid) and lower PCL (polycaprolactone) are the most widely studied polyesters in this area, especially with PS (polystyrene), PDMS (polydimethylsiloxane) or PTMSS (polytrimethylsilylstyrene) block combination. Therefore, the paper entitled "Ordered Nanoporous Polymers from Polystyrene-Polylactide Block Copolymers", AS Zalusky et al., J.AM. CHEM. SOC. 2002, 124, 12761-12773 and the title "Thin Film Self-Assembly of Poly ( Trimethylsilylstyrene-b- _{D, L} -lactide) with Sub-10 nm Domains ", JD Cushen et al., Macromolecules, 2012, 45, 8722-8728 respectively describe nanoscale regions with a size below 10 nm, and their periodicity Preparation of PS- b- PLA diblock copolymers and PTMSS- b- PLA diblock copolymers between 12 and 15 nm. Finally, the paper entitled "High χ-low N Block Polymers: How Far Can We Go?", C. Sinturel et al., ACS Macro Letters, 2015, 4, 1044-1050 describes the combination of PLA and PS, PDMS or PTMSS. Block copolymers, and it has been confirmed that block copolymers with low number average molecular weight (generally below 20,000 g / mol) are capable of constructing nanometer regions with a size below 10 nm and a cycle L ₀ below 20 nm.

The applicant is more particularly concerned with polyesters of the polylactone type. Because of its biodegradability and biocompatibility, since Peter ’s polymers have certain industrially interesting properties in various fields, the ring-opening polymerization of lactones has been carried out for several years. the study. Therefore, copolymers with biodegradable polyesters can be used as encapsulants for drugs or as biodegradable implants, especially in orthopedics, to avoid the need to remove metal parts (such as needles, etc.) in the past. ) Surgery. These polymers are also useful in coatings and plastic blends. The Applicant is therefore concerned about these polymers because of their biodegradability to incorporate them into block copolymers, which can be easily eliminated after nanostructured, and can be created with the intent Nanolithographic resist, residual porous film for DSA (directional self-assembly) lithography applications. Polycaprolactone and polybutyrolactone also have good physical and chemical properties and good thermal stability up to a temperature of at least 200-250 ° C.

Organic catalysts have been developed to enable ring-opening polymerization of lactones, particularly ε-caprolactone (indicated as "ε-CL" in the rest of the description). Patent applications WO2008104723 and WO200810472 and papers entitled "Organo-catalyzed ROP of ε-caprolactone: methanesulfonic acid competes with trifluoromethanesulfonic acid", Macromolecules, 2008, Vol. 41, pp. 3782-3784 have specifically confirmed that methanesulfonic acid has " "MSA" indicates the effectiveness as a polymerization catalyst for ε-caprolactone.

The above paper also describes that MSA can promote the controlled polymerization of ε-caprolactone cyclic monomers when combined with alcoholic protonic initiators. In particular, protonic initiators make it possible to control the average molar mass and chain ends well.

In addition, it has also been known that when the blocks of the block copolymer exhibit a high glass transition temperature T _g or melting temperature T _m , they must be annealed at a high annealing temperature to facilitate nanostructure. If the annealing process must be performed at high temperature (generally higher than 200 ° C.) and with slower segregation kinetics, this will cause stability problems and higher processing costs in the copolymer.

The applicant is therefore directed to the behavior of block copolymers containing biodegradable blocks.

The technical problem you want to solve

It is therefore an object of the present invention to overcome at least one disadvantage of the prior art. The present invention is particularly related to proposing a block copolymer film comprising at least one biodegradable first block, the block copolymer film being capable of being at a mild temperature (less than 200 ° C and preferably less than 180 ° C) After annealing with a power of less than 30 minutes, preferably a power of less than 15 minutes, the nanostructure itself is structured into a nano area with a controlled period of less than 20nm. Technical means to solve problems

Surprisingly, nano-structured block copolymer films have been found in the nano region, the copolymer comprising at least one biodegradable first block and a second block having a chemical nature different from the first block. The block copolymer is characterized in that the first biodegradable block is amorphous and that the second block is derived from an oligomer or polymer having a hydroxyl functionality on at least one end and serves as the first block. Monoblock polymerization initiator. The block copolymer film is allowed to be manufactured at a temperature between 130 and 170 ° C and a period between 5 and 10 minutes. Nano area.

According to other optional characteristics of the block copolymer film:-the amorphous biodegradable first block is a polyester type;-the amorphous biodegradable polyester first block is selected from unsubstituted or Ε- or δ-lactone polymers substituted with aryl or alkyl groups;-the amorphous biodegradable polyester-type first block is selected from ε-caprolactone and selected from aryl- or alkyl-substituted an amorphous caprolactone copolymer (PCL _am ) formed by at least one other comonomer of ε- or δ-lactone;-the block copolymer is a diblock or triblock copolymer;-constituting the amorphous Co-monomer of caprolactone copolymer (PCL _am ) ε-caprolactone (ε-CL) and 4-phenyl-caprolactone (4-Ph-ε-CL);-between ε-CL / The molar ratio between the 4-Ph-ε-CL comonomers is comprised between 6/1 and 3/1, preferably between 6/1 and 4/1;-the amorphous caprolactone copolymer (PCL _am ) the number average molecular weight of each block comprises between 1000 and 30,000 g / mol, preferably between 2000 and 15000 g / mol;-the number average molecular weight of the block copolymer is between 7000 and 33,000 g / mol;- The molar ratio of the ε-caprolactone and 4-Ph-ε-CL comonomers contained in the hydroxyl functionality of the giant initiator is between 16/1 and 130/1;- This second block is derived from an oligomer or a mono- or polyhydroxylated polymer selected from: (alkoxy) polyalkanediols, such as (methoxy) polyethylene glycol (MPEG / PEG) , Polypropylene glycol (PPG) and polybutylene glycol (PTMG); poly (alkyl) alkylene adipate glycols, such as poly (2-methyl-1,3-propaneadipate) Alcohol (PMPA) and poly (1,4-butylene adipate) glycol (PBA); mono- or bis-hydroxymethyl polysiloxanes (polysiloxanes, mono- or di-carbinols), such as, mono -Or dihydroxylated polydimethylsiloxane (PDMS), or, if desired, hydrogenated mono- or dihydroxylated polydiene, such as α, g-dihydroxylated polybutadiene or α, Omega-dihydroxylated polyisoprene, preferably a hydrogenated or non-hydrogenated hydroxytetrapolybutadiene; or a mono- or polyhydroxylated polyene, such as a mono- or polyhydroxylated polyene Isobutene; modified or unmodified polysaccharides, such as starch, chitin, chitosan, polydextrose, and cellulose; or from Vinyl co-oligomers or copolymers of enoic, methacrylic, styrene or diene polymer families, derived from acrylic, methacrylic, styrene or diene monomers and Copolymerization reaction between functional monomers, or vinyl copolymer obtained by free radical polymerization, which is controlled or uncontrolled, wherein the free radical initiator and / or control agent has at least one hydroxyl or thiol function Sex

Starting from this block copolymer film, a nanolithographic resist can be manufactured by removing a biodegradable amorphous first block to form a porous pattern having a period L ₀ ≤ 20 nm perpendicular to the surface to be etched.

Other unique features and advantages of the present invention will become apparent after reading the following description provided by way of illustration and non-limiting example.

The term "monomer" is used in reference to a molecule capable of polymerizing.

The term "polymerization" is used in reference to a method of converting a monomer or a mixture of monomers into a polymer.

The term "oligomer" is used to refer to a small polymerizable compound containing between 2 and 30 monomers, that is, having a degree of polymerization between 2 and 30.

As used herein, the term "copolymer block" or "block" refers to a polymer that groups several monomer units of several types or the same type.

The term "block copolymer" as used herein refers to a polymer containing at least two of the foregoing blocks, the two blocks being different from each other and having phase separation parameters that make them incompatible with each other and below the decomposition of the block copolymer The temperature is separated into nanometer regions.

The term "miscibility" as used above refers to the ability of two compounds to be completely mixed together to form a homogeneous phase.

The block copolymer according to the present invention advantageously contains a biodegradable first block, which can be easily eliminated after the nanostructure of the copolymer is structured, so that a porous film used as a nanolithography resist can be manufactured. The block copolymer contains at least one other block that is different from the first block and is incompatible with the first block, that is, they cannot be mixed and they separate into nano-domains.

Advantageously, the first biodegradable block exhibits an amorphous structure.

More specifically, the amorphous biodegradable first block is a polyester type. Among the polyesters capable of forming this amorphous first block, there may be selected, for example, an amorphous ε-lactone polymer which is mono-substituted by a linear or branched chain, optionally substituted by an aryl group or an alkyl group, or Amorphous polymers of linear or branched mono-substituted, optionally substituted δ-lactones with aryl or alkyl groups. This can be, for example, a polymer of the amorphous polybutyrolactone type (labeled PBL _am ), or a polymer of the amorphous polycaprolactone type (note, for the sake of simplicity, the PCL _am ) .

In a more preferred embodiment, the amorphous first block is amorphous polycaprolactone (PCL _am ). PCL is a semi-crystalline polymer that exhibits a mild melting point T _M (60 ° C) and a low glass transition temperature T _g (-60 ° C). Because of these mild to low temperatures, the applicant claims that they will facilitate phase separation of the block copolymers at mild annealing temperatures (preferably below 200 ° C) and with favorable kinetics (preferably below 30 minutes).

However, the applicant observed that, surprisingly, the block copolymers containing the semi-crystalline polycaprolactone PCL blocks did not exhibit any nano-sized structure. Even if the nanostructures of these block copolymers are annealed at a temperature of the order of 100 ° C. for 12 hours, when they are cooled to normal temperature, the nanostructured crystals that destroy the obtained block copolymer appear to the extent that they are at normal temperature The block copolymer did not exhibit any nanostructured. Conversely, when ε-caprolactone and a comonomer with similar properties make the polycaprolactone block amorphous by statistical copolymerization, it is annealed at a temperature of the order of 100 ° C for 12 hours and then cooled. Even at room temperature, separation was observed in the solid state structured in nanometer size.

The second block is formed of an oligomer or polymer that is chemically incompatible with the first block and includes alcohol functionality on at least one end. This alcohol-functionalized second polymer was able to act as a giant initiator for the polymerization of the first block, in particular in the presence of methanesulfonic acid (MSA) as a catalyst. When it contains hydroxyl functionality on only one end, it can make a diblock copolymer with PCL. When it contains a hydroxy functionality at both ends, it can synthesize a triblock copolymer with PCL blocks at the endpoints.

In the case of manufacturing a film based on this block copolymer containing amorphous PCL (PCL _am ) blocks, the annealing treatment at a temperature between 130 and 170 ° C. is extremely short, advantageously less than 10 minutes And preferably between 1 and 5 minutes, it is sufficient to observe the nanostructure in the block copolymer film. In this case, the film is treated by annealing at a temperature lower than 180 ° C, which improves the mobility of the polymer chain and accelerates the structuring kinetics of the copolymer.

Preferably, the amorphous caprolactone copolymer is used to form the first polyester block of the block copolymer, and is obtained by the copolymerization reaction of ε-caprolactone and a monomer having a similar nature. It is understood that a monomer substantially similar to ε-CL refers to a mono-substituted ε-lactone or a mono-substituted δ-lactone type monomer. Advantageously, the amorphous PCL is thus formed from ε-caprolactone and at least one other comonomer selected from aryl- or alkyl-substituted ε- or δ-lactones. Of these monomers with similar nature, 4-phenyl-caprolactone (labeled 4-Ph-ε-CL in the rest of the description) is a preferred comonomer because it means that it can have a low mole fraction Rate, on the order of 15 to 20%, to produce amorphous caprolactone copolymers. Therefore, caprolactone and 4-phenyl-caprolactone comonomers form a statistical poly (4-phenyl-caprolactone- r -caprolactone) copolymer, which is hereinafter designated as P (4-Ph-ε -CL–r-ε-CL).

The fact that the PCL crystal block is replaced by an amorphous block composed of statistical caprolactone copolymers has been described in the literature, but the nanostructure of a block copolymer used as a nanolithography resist has not been achieved. purpose. What's more, in these cases, the proportion of comonomers required to suppress the crystallinity in PCL is high and is included between 33 and 50%.

Accordingly, R. Jérôme, RE Prud'home et al. Have shown in the paper entitled "Synthesis, characterization, and miscibility of caprolactone random copolymers," Macromolecules, 1986, 19, 1828 and 6-caprolactone and 6- The statistical copolymerization of Me-ε-caprolactone produced an amorphous copolymer with a 50/50 ratio between monomers. These amorphous copolymers exhibit better miscibility with PVC than semi-crystalline polycaprolactone, because crystal formation reduces this miscibility. These amorphous copolymers are biodegradable and have been tried to make subcutaneous implants for drug delivery.

Elasticity has also been shown in the paper entitled "Triblock copolymer of ε-caprolactone, L-lactide and trimethylene carbonate: biodegradability and elastomeric behavior," J. Biomedical Materials Research, part A 2011, 99A, 38 LK Widjaja et al. In the case of plastic polymers, the effect of crystalline / amorphous nature. When a tri-block PLA- b- PCL- b- PLA copolymer is prepared, the semi-crystalline nature of PCL hardens the central block, thereby reducing the elastic nature. Due to the random copolymerization of ε-caprolactone and trimethylene carbonate, a central amorphous block is obtained at a monomer ratio of 50/50, which significantly improves the elasticity.

Finally, under the heading "Poly (lactide) -block-poly (ε-caprolactone-co-ε-decalactone) -block-poly (lactide) copolymer elastomers," Polym. Chem. 2015, 6, 3641, M. Hillmyer et al. al. paper, research triblock copolymer PLA- b -PCL-b-PLA (which is half the center crystalline PCL block) and PLA- b -P (CL-r- DL) - b -PLA ( The central block P (CL- r- DL) is amorphous and the CL / DL ratio is 66/33). In both cases, the presence of microphase separation is shown, depending on the composition, resulting in a layered or cylindrical morphology. The resulting structure is micron-sized rather than nano-sized. This paper therefore does not confirm that the semi-crystalline or amorphous nature has an effect on the separation properties of the resulting copolymers. Furthermore, the establishment of additional experimental materials as an appendix to this paper explained that performing SAXS analysis showed that micro-separation of the phases was performed after annealing at 120 ° C for 12 hours and then at 60 ° C for 8 hours. The structuring power of these copolymers is therefore extremely low.

The second polymer which forms the second block of the block copolymer according to the invention and acts as a macroinitiator for the polymerization of the first block, and more particularly a statistical copolymer of caprolactone, can be advantageously selected from Oligomer or mono- or polyhydroxylated polymer, in particular selected from: (alkoxy) polyalkanediols, such as (methoxy) polyethylene glycol (MPEG / PEG), polypropylene glycol (PPG ) And polybutylene glycol (PTMG); poly (alkyl) alkylene adipate glycols, such as poly (2-methyl-1,3-propane adipate) glycol (PMPA) and Poly (1,4-butylene adipate) glycol (PBA); mono- or di-hydroxymethyl polysiloxanes, such as mono- or dihydroxylated polydimethylsiloxane (PDMS) ); Hydrogenated, α-hydroxylated or α, ω-dihydroxylated polydiene as required, such as α, g-dihydroxylated polybutadiene or α, ω-dihydroxylated polyiso Pentadiene; mono- or polyhydroxylated polyenes, such as mono- or polyhydroxylated polyisobutylene; modified or unmodified polysaccharides, such as starch, chitin, chitosan, Polydextrose and cellulose; and mixtures thereof.

According to another possibility, the macroinitiator may be a vinyl co-oligomer or copolymer from an acrylic, methacrylic, styrene or diene polymer family, which is derived from an acrylic, methyl Acrylic, styrene or diene monomers and functional monomers with hydroxyl groups (eg, hydroxylated methacrylic or acrylic monomers, such as 4-hydroxybutyl acrylate, hydroxyethyl acrylate, and methyl Copolymerization reaction between hydroxyethyl acrylate). This polymerization reaction can be performed according to a conventional radical method, a controlled radical method, or an anionic method.

According to another possibility, the macroinitiator may be a vinyl copolymer obtained by controlled or uncontrolled free radical polymerization, wherein the free radical initiator and / or the control agent has at least one hydroxyl or mercapto function Sex.

Preferably, the macroinitiator is advantageously selected from hydroxylated polyolefins, that is, any polymer derived from an olefin bearing at least one hydroxylated functionality or a hydroxy telechelic functionality. Polydiene is a particular target, and among polydiene, polybutadiene and the most specific hydroxyl telechelic polybutadiene are preferred.

More specifically, the hydroxy telechelic polybutadiene-based Cray Valley is a polymer sold under the trade name Kasol® and more particularly Krasol LBH-P3000® and Krasol HLBH-P3000®. Krasol LBH-P3000 ^® is a polybutadiene produced by anionic polymerization with a number average molecular weight M _{n of} about 3500 g / mol. Krasol HLBH-P3000 ^® is a hydrogenated polybutadiene with a number average molecular weight M _{n of} about 3100 g / mol. This hydroxy telechelic polybutadiene then acts as a giant initiator for the polymerization reaction of the amorphous first block, and more particularly a comonomer constituting an amorphous caprolactone copolymer (PCL _am ). These dihydroxylated macroinitiators enable the synthesis of PCL-Krasol®-PCL triblock copolymers with hydrogenated or unhydrogenated polybutadiene (PBT) -type central blocks.

The blends of Krasol LBH-P3000 ^® and Krasol HLBH-P3000 ^{® used} are as follows:

Each block of the amorphous copolymer PCL, PCL _am , preferably has a number average molecular weight between 1000 and 30,000 g / mol, preferably between 2000 and 15,000 g / mol;

The number average molecular weight of the obtained block copolymer is between 7000 and 33,000 g / mol.

In order to obtain amorphous poly (e-CL- r -4-Ph-e-CL) copolymer, the molar ratio of e-CL / 4-Ph-e-CL is between 6/1 and 3/1. It is preferably between 6/1 and 4/1, and this corresponds to a mole ratio of 4-Ph-e-CL preferably between 15 and 20%.

The obtained block copolymer is then deposited on a substrate in the form of a film. The method for manufacturing this block copolymer film includes the following steps: a macroinitiator (for example, a hydroxylated polyolefin-type macroinitiator, and more particularly, a hydroxylated or dihydroxylated polybutadiene) and ε- CL or 4-Ph-ε-CL comonomers are mixed in a solvent to synthesize this block copolymer, which is performed in the presence of methanesulfonic acid (as a catalyst for the polymerization reaction of the previously proposed comonomer), To selectively obtain a block copolymer of PCL _am -PBT-PCL _am in one step. The solvent is advantageously selected from toluene, ethylbenzene and xylene. However, toluene is superior to the other two solvents. The catalyst is then eliminated and the resulting block copolymer solution is applied in the form of a film to a surface to be etched whose surface energy has been previously neutralized. The solvent of the solution is evaporated and the film is annealed at a predetermined temperature between 130 and 170 ° C for a period of less than 30 minutes, preferably less than 15 minutes, to ensure that the copolymer is perpendicular to the surface to be etched. The nanometer region is structured. Annealing temperatures between 130 and 170 ° C are sufficient to produce nanometers in a short time on the order of minutes, preferably less than 15 minutes, and more preferably less than 5 minutes and ideally between 1 and 2 minutes structure.

However, from the viewpoint of controlling the surface energy, generally, in the case of lithography, the desired structuring, such as generating a nano region perpendicular to the surface, requires the production of a surface on which a copolymer solution is deposited. In known possibilities, random copolymers (whose monomers may be completely or partially the same as those used in the block copolymer to be deposited) are deposited on the surface. In advanced papers, Mansky et al. (Science, Vol. 275, pages 1458-1460, 1997) provide a good description of this technology and are now familiar with this technology.

Among the favorable surfaces, mention may be made of silicon (which has a naturally or thermally generated oxide layer), germanium, platinum, tungsten, gold, titanium nitride, graphene, BARC (bottom antireflection coating) Or any other anti-reflective layer used in lithography.

Once the surface is made, according to techniques known to those skilled in the art (e.g. spin-coating, doctor blade, knife system, or gap mold system technology), any other technique (e.g., dry deposition, That is, the deposition does not include dissolution in advance), the solution of the block copolymer according to the present invention is deposited and the solvent is then distilled off.

Heat treatment is then performed, which enables the block copolymer to be more correctly organized, that is, to obtain phase separation between nano regions in particular, its size is less than 10 nm, it has a controlled morphology and the period is less than 20 nm. The preferred orientation is perpendicular to the surface to be etched and reduces the number of defects. The temperature T of this heat treatment is preferably made lower than 180 ° C and higher than the maximum glass transition temperature of the blocks constituting the copolymer. It is carried out in a solvent atmosphere, either by heat, or by a combination of these two methods.

Depending on whether the macroinitiator is mono- or dihydroxylated, the resulting copolymer is a PCL _am -PBT-type diblock copolymer or a PCL _am -PBT-PCL _am -type triblock copolymer.

The block copolymer according to the present invention is preferably synthesized in a temperature range from 20 to 120 ° C and more preferably between 30 and 60 ° C, especially when the solvent is toluene. In fact, when the macroinitiator is a hydrogenated or non-hydrogenated hydroxytetrapolybutadiene, a PCL _am -b having a number average molecular weight M _{n of} up to 33,000 g / mol can be obtained at a temperature of about 30 ° C within a few hours -Krasol®- b -PCL _am or PCL _am -b-Krasol®H- b -PCL _am block copolymer and after purification, its yield is greater than or equal to 85%.

The mole of the initiator / catalyst (MSA) is preferably between 1/1 and 1/2.

Finally, the reagents used in this method are preferably dried before use, especially by vacuum treatment, distillation, or using an inert desiccant.

The cylindrical or layered morphology of the nanoregions formed in this way depends on the molar ratios of the comonomers ε-CL and 4-Ph-ε-CL to the macroinitiator in the starting mixture, but also depends on the formation The macroinitiator nature of the second block of the block copolymer and its degree of polymerization.

The moles of the ε-CL and 4-Ph-ε-CL comonomers relative to the macro-initiator functionality are preferably comprised between 16/1 and 130/1.

After the block copolymer has been synthesized, it has been deposited in the form of a film on the surface to be etched and has been subjected to an annealing treatment according to the previous description, it is advantageous to remove the first block of biodegradable PCL _am to form Nano-etching resist on the surface to be etched and having a porous pattern with a period L ₀ ≦ 20 nm.

The block copolymer according to the present invention can therefore obtain a block assembly perpendicular to the surface to be deposited with a clear phase separation, and obtain a small size of about one nanometer to a few nanometers and a controlled morphology and less than or equal to 20nm period nano region. This block copolymer thus allows better control of the lithography method, which has a high resolution and is compatible with current requirements regarding the dimensions of the component.

Crystals in a block copolymer containing PCL blocks obtained by statistical copolymerization of e-CL and 4-Ph-e-CL (using only 15 to 20 mol% of 4-Ph-e-CL comonomer) The degree of inhibition is such that a block copolymer that can be separated is produced, resulting in a nanometer-sized structure, while a copolymer containing a semi-crystalline PCL block has no nanostructure observed.

What's more, from amorphous polyesters, and more particularly from amorphous PCL, the copolymers obtained can be separated at low molecular weight (basically comprised between 4000 and 30,000 g / mol) due to the low annealing Temperature (<180 ° C) and extremely short period (<10 minutes) treatments were achieved. The morphology of a well-defined area is obtained with a low period L ₀ (<20 nm).

This behavior is confirmed in the context of DSA (Directional Self-Assembly) lithography applications (in which an attempt is made to obtain a nanostructure with a periodic structure with a very small copolymer cycle, if possible, at low temperature and in a short time to obtain It is particularly advantageous in lithography resists with very high resolution. The following examples illustrate, without limitation, the scope of the invention:

Aiming at the ring-opening polymerization reaction of cyclic lactones and carbonates and the preparation of block copolymers using sulfonic acid as a catalyst, semi-crystalline polycaprolactone (PCL) and amorphous poly (4-phenyl-hexanoic acid) were prepared. Lactone-r-caprolactone) based triblock copolymer for comparison. Krasol LBH-P3000® and Krasol HLBH-P3000® dihydroxylated telechelic polymers act as macroinitiators to have hydrogenated or unhydrogenated polybutadiene-type central blocks.

The sulfonic acid used as a catalyst in the copolymerization reaction is methanesulfonic acid (MSA).

In the presence of MSA as a catalyst, the copolymerization reaction of ε-CL monomer and poly (4-Ph-ε-CL-r-ε-CL) copolymer using KrasolLBH and KrasolHLBH macroinitiators, respectively:

The following method was performed using the following general procedure.

The MBraun SPS-800 solvent purification system was used to dry toluene. Methanesulfonic acid (MSA) was used for further purification. Diisopropylethylamine (DIEA) was dried and distilled over CaH ₂ and stored in potassium hydroxide (KOH). Ε-caprolactone dried over CaH ₂ and then distilled was stored in an inert atmosphere. 4-Ph-ε-CL was recrystallized from toluene, then dried over P ₂ O ₅ and stored in an inert atmosphere.

The Schlenk tube is dried under vacuum with a heat gun to remove any trace of moisture.

The reaction was monitored by ¹ H NMR (proton nuclear magnetic resonance) and size exclusion chromatography (SEC) on Bruker Avance 300 and 500 instruments in THF. For this purpose, a sample was taken, neutralized with DIEA (diisopropylethylamine), evaporated and dissolved in a suitable solvent for its characteristics. ¹ H NMR can quantify the degree of polymerization (DPs) of ε-CL and 4-Ph-ε-CL comonomers. This is achieved by measuring the functional group with OC (= O) and the functional group with C = O. The integral ratio of the half of the signal of the -CH ₂ -group to the signal of the CH ₂ proton with the -OH functional group on the initiator was obtained. The spectra were recorded on a 300 MHz spectrometer in deuterated chloroform. The number average molecular weight Mn and polydispersity (D) of the obtained copolymer samples were determined by size exclusion chromatography SEC in polystyrene calibration in THF.

By differential scanning card meter (indicated by DSC), the glass transition and crystallinity can be studied. DSC is a thermal analysis technique that determines the difference in heat exchange between a sample to be analyzed and a control during a phase transition. The study was performed using a Netzsch DSC204 differential scanning card meter.

The card gauge analysis was performed at a temperature between -80 and 130 ° C, and the temperature value was recorded during the second temperature rise (at a rate of 10 ° C / minute).

Through the analysis of small-angle X-ray scattering (expressed as SAXS), it is possible to study the structural properties of the block copolymer synthesized at a size smaller than 100 nm. This analysis technique consists in inducing monochromatic rays to scatter through the sample to be analyzed. Collect the scattering intensity that varies with the scattering angle passing through the sample. The scattering angle is very close to the direct beam. Scattered photons provide information about changes in electron density in heterogeneous materials. For SAXS analysis, the BM-26B station of the DUBBLE line of the Nanostar SAXS (Bruker) device or the European Synchrotron Radiation Device (ESFR) was used.

The following examples are prepared and compared based on semi-crystalline polycaprolactone (PCL) on the one hand and amorphous poly (ε-CL-co-4-Ph-ε-CL) on the other. Block copolymer.

In all cases, the polymerization of PCL or P (CL-co-4-Ph-CL) as a whole was carried out with a very good degree of control, that is, the polyester block was effectively incorporated into polybutadiene (Krasol ) On the hydroxylated end and has minimal effect on the transfer reaction. The block structure of this copolymer was confirmed by NMR and SEC analysis of the polymer.

DSC and SAXS and / or microscope analysis have also been used to study the separation ability of these copolymers and their ability to become nanostructures. The results of the analysis are summarized in Table I below. Example 1 (ComparativeExample): a triblock of poly - ₄₃ (E-caprolactone) - block -Krasol LBH-P3000- block - poly (E - caprolactone) copolymer of Preparation ₄₃

The macroinitiator (Krasol LBH-P3000, 1 equivalent, 1.5 g) and e-CL (90 equivalents, 4.11 g) were weighed into a glove box and added to a dry Schlenk bottle. This Schlenk bottle was placed under a controlled argon atmosphere, after which a solvent (9 ml of toluene, [ε-CL] ₀ = 4 mol / l) and methanesulfonic acid (1 equivalent, 78 μl) were added in this order. The reaction medium is stirred under argon at 30 ° C for 2 hours and 30 minutes. Once the monomer was completely consumed (as known by ¹ H NMR monitoring), an excess of diisopropylethylamine (DIEA) or Amberlyst 21 was added to neutralize the acid catalyst. The solvent was then evaporated under vacuum. The resulting polymer was then dissolved in a minimum amount of dichloromethane and then precipitated by the addition of cold methanol, filtered and dried under vacuum.

The polymerization of ε-CL monomer and macroinitiator is as follows: The results are as follows:

PCL ₄₃ -b-Krasol® -b- PCL ₄₃ triblock copolymer was obtained with a conversion of 99% and a yield higher than 90%.

SEC : M _n = 18,000 g / mol; Đ = 1.18

DSC : _Tg : -55.4 ° C; _Tf : 52.7 ° C; overall crystallinity = 45%

¹ H NMR (CDCl ₃ , 300 MHz) : 5.70-5.20 (m, 40 × 1H, CH CH = CH ₂ + 2 × 2 × 10H, -CH- CH = CH -CH-), 5.00-4.80 (m, 1 × 40 × 2H, CH-CH = CH ₂ ), 4.10-4.00 (m, 86 × 2H, O CH ₂ CH ₂ ), 3.70-3.60 (m, 2 × 2H, CH ₂ OH at the end of the chain), 2.40- 2.20 (m, 86 × 2H, CO CH ₂ ), 2.20-1.75 (m, 40 × 1H, CH CH = CH ₂ + 2 × 2 × 10 × 2H, -CH ₂ -CH = CH- CH _2- ), 1.70-1.50 (m, 2 × 86 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O), 1.45-1.10 (m, 86 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O, 40 × 2H , CH ₂ -CH ₂ -CH).

Composition 2 (Invention) "PCL _am. " ₄₂ -b -Krasol LBH-P3000- b- "PCL _am. " ₄₂ Preparation of triblock copolymer

Macroinitiator (Krasol LBH-P3000, 1 equivalent, 0.53g) and ε-CL (72 equivalents, 1.16g) and 4-Ph-ε-CL (18 equivalents, 0.48g) were weighed into a glove box and added to dryness Schlenk in the bottle. This Schlenk bottle was placed under a controlled argon atmosphere, after which the solvent (12.6 ml of toluene, [M] ₀ = 1 mol / l) and methanesulfonic acid (2 equivalents, 19 μl) were added in this order. The reaction medium is stirred under argon at 30 ° C for 1 hour and 10 minutes. Once the monomer was completely consumed (as known by ¹ H NMR monitoring), an excess of diisopropylethylamine (DIEA) or Amberlyst 21 was added to neutralize the acid catalyst. The solvent was then evaporated under vacuum. The resulting polymer was then dissolved in a minimum amount of dichloromethane and then precipitated by the addition of cold methanol, filtered and dried under vacuum.

The results are as follows:

" PCL _am. " ₄₂ - b -Krasol LBH-P3000- b- " PCL _am. " ₄₂ triblock copolymer was obtained with a conversion of 88% and a yield higher than 83%.

SEC : M _n = 13,000 g / mol; Ð = 1.23

DSC : _Tg : -53.8 ° C; _Tf : -amorphous

¹ H NMR (CDCl ₃ , 300 MHz) : 7.40-7.10 (m, 12 × 5H, Ph , CH Cl ₃ ), 5.70-5.20 (m, 40 × 1H, CH CH = CH ₂ + 2 × 2 × 10H,- CH- CH = CH -CH-), 5.00-4.80 (m, 1 × 40 × 2H, CH-CH = CH ₂ ), 4.05-3.75 (m, 70 × 2H, CH ₂ O (C = O) C + 12 × 2H, CH ₂ O (C = O) C), 3.70-3.45 (m, 2 × 2H, CH ₂ OH at the end of the chain), 2.70-2.50 (m, 12 × 1H, CH (C ₆ H ₅ )) , 2.40-2.20 (m, 70 × 2H, CO CH ₂ ), 1.75-2.20 (m, 12 × 2H, O (C = O) CH ₂ , 12 × 2 × 2H, O (C = O) CH ₂ CH ₂ CH CH ₂ , 40 × 1H, CH CH = CH ₂ + 2 × 2 × 10 × 2H, -CH ₂ -CH = CH- CH _2- ), 1.70-1.50 (m, 2 × 70 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O), 1.45-1.10 (m, 2 × 40 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O, 40 × 2H, CH ₂ -CH ₂ -CH).

Example 3 (comparative example): triblock poly ( ε -caprolactone) ₃₆ -Block-Krasol HLBH-P3000-block-poly ( ε -caprolactone) ₃₆ Preparation of copolymer

The macroinitiator (Krasol HLBH-P3000, 1 equivalent, 0.33 g) and ε-CL (70 equivalent, 0.75 g) were weighed into a glove box and added to a dry Schlenk bottle. This Schlenk bottle was placed under a controlled argon atmosphere, after which a solvent (6.6 ml of toluene, [ε-CL] ₀ = 1 mol / l) and methanesulfonic acid (2 equivalents, 7.3 μl) were sequentially added. The reaction medium is stirred under argon at 30 ° C for 1 hour and 30 minutes. Once the monomer was completely consumed (as known by ¹ H NMR monitoring), an excess of diisopropylethylamine (DIEA) or Amberlyst 21 was added to neutralize the acid catalyst. The solvent was then evaporated under vacuum. The resulting polymer was then dissolved in a minimum amount of dichloromethane and then precipitated by the addition of cold methanol, filtered and dried under vacuum.

The results are as follows:

Poly ( e -caprolactone) ₃₆ - block- Krasol HLBH-P3000-block-poly ( e -caprolactone) ₃₆ triblock copolymer was obtained with a conversion of 99% and a yield higher than 90% .

SEC : M _n = 20,000 g / mol; Đ = 1.04

DSC : _Tg : -55 ° C; _Tf : 53.4 ° C; overall crystallinity = 42%

¹ H NMR (CDCl ₃ , 300 MHz) : 4.10-4.00 (m, 72 × 2H, CH ₂ O (C = O) C), 3.70-3.60 (m, 2 × 2H, CH ₂ OH at the end of the chain), 2.40 -2.20 (m, 72 × 2H, CO CH ₂ ), 1.70-1.50 (m, 2 × 72 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O), 1.45-0.95 (m, 72 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O, 36 × 1H, CH ₂ - CH -CH ₂ + 2 × 36 × 2H, CH- CH ₂ -CH ₃ + 2 × 4 × 10 × 2H, -CH ₂ -CH ₂ -CH _2- ), 0.95-0.75 (m, 36 × 3H, CH ₂ - CH ₃ ). Example 4 ( Invention ) : Preparation of " PCL _am. " ₃₆ -b-Krasol HLBH-P3000- b- " PCL _am. " ₃₆ triblock copolymer

Giant initiator (Krasol HLBH-P3000, 1 equivalent, 0.55g) and e-CL (56 equivalents, 1.16g) and 4-Ph-e-CL (14 equivalents, 0.48g) were weighed into a glove box and added to dry Schlenk in the bottle. This Schlenk bottle was placed under a controlled argon atmosphere, after which a solvent (3.7 ml of toluene, [β-BL] ₀ = 4 mol / l) and methanesulfonic acid (2 equivalents, 45 μl) were added in this order. The reaction medium is stirred at 30 ° C. for 1 hour and 15 minutes under argon. Once the monomer was completely consumed (as known by ¹ H NMR monitoring), an excess of diisopropylethylamine (DIEA) or Amberlyst 21 was added to neutralize the acid catalyst. The solvent was then evaporated under vacuum. The resulting polymer was then dissolved in a minimum amount of dichloromethane and then precipitated by the addition of cold methanol, filtered and dried under vacuum. The results are as follows:

"PCL _am. " ₃₆ -b-Krasol HLBH-P3000- b- "PCL _am. " ₃₆ triblock copolymer was obtained with a conversion of 99% and a yield higher than 90%.

SEC : M _n = 14,500g / mol; Đ = 1.23

DSC : _Tg : -54.2 ° C; _Tf :-amorphous

¹ H NMR (CDCl ₃ , 300MHz) : 7.35-7.00 (m, 11 × 5H, Ph , CH Cl ₃ ), 4.10-3.75 (m, 56 × 2H, CH ₂ O (C = O) C + 11 × 2H , CH ₂ O (C = O) C), 3.70-3.45 (m, 2 × 2H, CH ₂ OH at the end of the chain), 2.70-2.50 (m, 11 × 1H, CH (C ₆ H ₅ )), 2.40- 2.20 (m, 56 × 2H, CO CH ₂ ), 2.15- 1.75 (m, 11 × 2H, O (C = O) CH ₂ , 11 × 2 × 2H, O (C = O) CH ₂ CH ₂ CH CH ₂ ), 1.70-1.50 (m, 2 × 56 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O), 1.45-0.95 (m, 56 × 2H, COCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ O, 36 × 1H, CH ₂ - CH -CH ₂ + 2 × 36 × 2H, CH- CH ₂ -CH ₃ + 2 × 4 × 10 × 2H, -CH ₂ -CH ₂ -CH _2- ), 0.95-0.75 ( m, 36 × 3H, CH ₂ - CH ₃ ).

Because the two blocks have very similar T _g (PCL, -60 ° C and Krasol-55 ° C), thermal analysis (DSC) of the copolymers studied showed a single glass transition temperature. Given that the T _g values of the corresponding homopolymers are similar (Tg for PCL = -60 ° C and Tg for Krasol = -55 ° C), it is difficult to infer conclusions about these block separation capabilities based solely on DSC analysis. It should also be noted that block copolymers containing PCL blocks have a semi-crystalline nature, while block copolymers with PCL _am blocks have an amorphous nature.

Depending on whether the block copolymer is incorporated into a PCL or PCL _am chain end block, SAXS analysis provides more information about the different behaviors of the block copolymer. As far as (semi-crystalline) PCL-based copolymers are concerned, there is no nanostructure with a well-defined morphology, but rather phase separation simply due to the crystallinity of PCL, while the amorphous PCL / Krasol phase appears to be mutually soluble. On the other hand, in the case of the PCL _am block, a nanostructure with a well-defined morphology was observed, especially when hydrogenated Krasol was used. In the cases observed and shown in Table I below, the nanostructure is cylindrical. Figure 1 illustrates the curve obtained from the SAXS analysis of the PCL _am.65 - b -Krasol H- b -PCL _am.65 film, where q corresponds to the diffusion angle at the wavelength used, and q * more particularly corresponds to the strongest diffusion. The q / q * values obtained from the different peaks (1, √4, √7, √9) are characterized by a cylindrical hexagonal arrangement with an average period L ₀ of 17.3 nm. The SAXS analysis of the block copolymer is performed, for example, on a polymer obtained during synthesis-purification after annealing at 100 ° C for 12 hours.

The triblock copolymers of Examples 5 to 9 in Table I below were synthesized in the same manner as described in Examples 1 to 4.

Then choose PCL _am -b-Krasol -b- PCL _am or PCL _am -b-Krasol H -b- PCL _am triblock copolymer, which results in a nanostructure, more specifically PCL _am -b-Krasol H -b- PCL _am for microscopic analysis. For this purpose, the copolymer solution was deposited on the surface as a 140 nm thick film, after which the solvent was evaporated and the film was annealed at a temperature between 130 and 170 ° C for a period between 5 and 10 minutes. In the examples in Table I above, the film of PCL _am.65 " -b- Krasol H- b- " PCL _am.65 was annealed at 150 ° C for 5 minutes. Thereafter, a cylindrical nanostructure with a period L ₀ equal to 17 nm was observed. The same PCL _am.65 " -b -Krasol H- b- " PCL _am.65 film was also annealed at 170 ° C for 10 minutes. Thereafter, a cylindrical nanostructure with a period L ₀ equal to 19 nm was observed. The microscopic analysis results confirmed a nanostructure having a nanometer region perpendicular to the surface and having an average period L ₀ below 20 nm. FIG. 2 is a result of observing this film (after annealing at 150 ° C. for 5 minutes) by an atomic force microscope (AFM), and FIG. 3 is an observation result of the same film after annealing at 170 ° C. for 10 minutes.

Block copolymers incorporating polyester blocks of amorphous caprolactone copolymers can therefore be separated, providing a nano-sized structure, while triblock copolymers of equivalent size based on semi-crystalline polycaprolactone are not Nanostructures were observed.

In addition, the copolymers obtained on the basis of PCL _am can be separated at a low molecular weight (basically less than 33,000 g / mol), making it possible to reach a wide range of structures with extremely small structuring periods below 20 nm depending on their composition. form.

This behavior is confirmed in the application area of DSA (Directional Self-Assembly) nanolithography (in which an attempt is made to obtain a nanostructure with a periodic structure with a very small copolymer period, in order to obtain a nanomicrograph with extremely high resolution Shadow inhibitor).

The copolymer according to the present invention differs greatly from the conventional PS-b-PMMA block copolymer which cannot obtain a cycle of less than 20 nm.

Figure 1 illustrates the curve obtained from the SAXS analysis of the PCL _am.65 - b -Krasol H- b -PCL _am.65 film, where q corresponds to the diffusion angle at the wavelength used, and q * more particularly corresponds to the strongest diffusion. The q / q * values obtained from the different peaks (1, √4, √7, √9) are characterized by a cylindrical hexagonal arrangement with an average period L ₀ of 17.3 nm. The SAXS analysis of the block copolymer is performed on a polymer such as obtained during synthesis-purification after annealing at 100 ° C for 12 hours.

FIG. 2 is a result of microscopic analysis, which confirms a nanostructure having a nanometer region perpendicular to the surface and having an average period L ₀ of less than 20 nm. This film can be observed by an electron force microscope (AFM) after annealing at 150 ° C for 5 minutes.

FIG. 3 is a result of microscopic analysis, which confirms a nanostructure having a nanometer region perpendicular to the surface and having an average period L ₀ of less than 20 nm. This film can be observed by an electron force microscope (AFM) after annealing at 170 ° C for 10 minutes.