CN108003350B - Silicon-containing organic-inorganic hybrid molecule and synthesis, assembly and application thereof - Google Patents

Abstract

The invention discloses a silicon-containing organic-inorganic hybrid molecule and synthesis, assembly and application thereof. The organic-inorganic hybrid molecule is an HBC-POSS molecule with larger molecular weight, which is formed by taking Hexabenzocoronene (HBC) as a core and connecting cage type silsesquioxane (POSS) around the Hexabenzocoronene (HBC) through a covalent bond. The molecule has two building units with nanometer sizes, can form an ordered structure with the size below 10nm through self-assembly, can obtain a nanometer template with the size below 10nm through oxygen plasma etching, and provides a new possibility for solving the bottleneck of the size of the nanometer template used for the semiconductor industry.

Description

Silicon-containing organic-inorganic hybrid molecule and synthesis, assembly and application thereof

Technical Field

The invention relates to a silicon-containing compound, in particular to synthesis, self-assembly and application of HBC-POSS series compounds with Hexabenzocoronene (HBC) as a core and silsesquioxane (POSS) at the periphery, belonging to the field of synthesis and self-assembly of material chemistry.

Background

In recent years, people's lives are extremely dependent on electronic products such as mobile phones and computers, and the response speed of these electronic products is related to the size of a silicon chip used by the electronic products. The linewidth of semiconductor industrial silicon chips has decreased from 90nm in 2004 to currently 14 nm. However, a bottleneck is encountered in obtaining silicon chips with smaller line width sizes at present, because the template used in the current manufacturing process is a photolithography technique using multiple exposures, which is a top-down method, and it is difficult to obtain nano-templates with smaller sizes for chip manufacturing unless special equipment, which is particularly expensive, is used. For this technical bottleneck, the bottom-up self-assembly method is considered to be expected to solve the dilemma of the size of 14nm or less.

Compared with the top-down method, the self-assembly has the following advantages: 1) the units are capable of spontaneous alignment; 2) the self-assembly forms a thermodynamically stable state, so that the material can be restored to an equilibrium state when being disturbed, thereby endowing the material with the self-repairing property; 3) the unit can be assembled in multiple scales and multiple levels, so that a complex assembly structure is obtained; 4) the self-assembly process is easy to regulate and control, and the self-assembly process can be regulated and controlled by means of stress shearing, solvent volatilization, a magnetic field, an electric field and the like. At present, the self-assembly of a block copolymer, especially the self-assembly of a diblock copolymer, is researched in the field of high molecules, and is an effective method which is expected to provide a template with the length of less than 10 nanometers. For a diblock copolymer, the microphase separation structure is related to three factors of polymerization degree (N), Flory-Huggins interaction parameter (chi) and volume fraction (f), when N and chi of two components of a block meet a certain condition, the ordered microphase separation structure can be formed, and along with the increase of a certain volume fraction, the ordered microphase separation structure can be changed from a spherical phase to a columnar phase, then to a bicontinuous phase, then to a lamellar phase and then to an inverse phase structure of the two components.

Self-assembly of block copolymers suffers from the following disadvantages: the block copolymer mainly forms a nano structure with the size of 20-100nm, and the block copolymer capable of forming a structure of 10nm or less is less in variety and more severe in conditions. Due to the dispersibility of the polymer and the uncertainty of the end groups, it is difficult to obtain a sharp phase interface, which is very disadvantageous for the fabrication of a chip template. And because the molecular weight of the polymer is larger, the chain segment movement is difficult, the regulation and control of the structure of the polymer need to take longer time, and a large-area ordered and defect-free structure is difficult to obtain.

Disclosure of Invention

The invention aims to overcome the problems of the existing self-assembly substrate, provides a novel organic-inorganic hybrid self-assembly substrate and a synthetic method thereof, utilizes the substrate to self-assemble a structure with the size of less than 10nm, and discusses the possibility of the substrate being applied as a nano template after being etched.

Specifically, aiming at the polydispersion of the macromolecule and the limitation of obtaining a structure below 10 nanometers, the invention adopts a nanoscale building unit to synthesize larger molecules with accurate structure and molecular weight of 2000-8000Da, and then forms an ordered structure with the period size below 10 nanometers through the secondary interaction force among the molecules. The invention adopts two nano-sized building units of Hexabenzocoronene (HBC) and silsesquioxane (POSS), takes the HBC as a core, connects a plurality of POSS around the HBC through covalent bonds to form HBC-POSS organic-inorganic hybrid molecules with larger molecular weight, and then obtains an ordered structure below 10nm through the self-assembly of films of the molecules. HBC is a molecule with a large conjugate plane, a highly ordered columnar structure can be formed in a body and a thin film, and the large plane structure and liquid crystallinity of HBC are also beneficial to the orientation of the ordered structure formed by HBC, so that large-area order is easy to realize. POSS is a cubic octagonal cage-shaped T8 POSS, which has an inorganic core and adjustable substituents on the periphery and can be regarded as very small silica nanoparticles. In the ordered structure formed by HBC-POSS, HBC always tends to form a columnar structure, and POSS forms a certain structure at the periphery of the column. For the structure, the HBC can be partially etched by using an oxygen plasma etching method, and a silicon-oxygen-carbon compound is left, so that the nano template with the thickness of less than 10nm can be obtained, and the nano template can be expected to be applied to chip manufacturing.

The HBC-POSS has a structural formula shown as a formula I:

in the formula I, R₁、R₂、R₃、R₄、R₅And R₆The same or different, at least two of which are represented by the following formula IIThe end is a group of cage type silsesquioxane, and the rest is alkyl or alkoxy:

in the formula II, R₇Is a chain group containing alkylene, alkenylene, alkynylene and/or arylene, and the wavy line represents a connecting bond with a Hexabenzocoronene (HBC) core; r₈、R₉、R₁₀、R₁₁、R₁₂、R₁₃And R₁₄The same or different, each independently is alkyl, alkoxy, cycloalkyl, alkenyl, alkynyl or aryl; x represents O or NH; n is an integer of 1 to 6.

R of the formula I₁、R₂、R₃、R₄、R₅And R₆When 1 to 4 of them are alkyl groups, they are preferably C13 to C30 linear or branched alkyl groups, and most preferably C13 to C30 branched alkyl groups, such as 2-hexyldecyl group, 2-decyltetradecyl group, and the like.

R of the formula I₁、R₂、R₃、R₄、R₅And R₆When 1 to 4 of the alkoxy groups are present, the alkoxy group is preferably a C1-C30 linear or branched alkoxy group, and more preferably a C12-C30 linear or branched alkoxy group. Such as hexyloxy, dodecyloxy, 7- (propoxymethyl) pentadecyl, and the like.

Further, R in formula II₇Preferably C1-C20, chain radicals containing alkylene, alkenylene, alkynylene or arylene groups, e.g. -C₁₀H₂₀-，-C₃H₆-，-C₆H₄-and so on.

In the formula II R₈、R₉、R₁₀、R₁₁、R₁₂、R₁₃And R₁₄Preferably C1-C18 alkyl, cycloalkyl, aryl, alkoxy, such as isobutyl, cyclohexyl, cycloalkyl, phenyl, ethoxy, propoxy and the like.

Several specific examples of the HBC-POSS hybrid organic-inorganic molecules of the present invention are given below:

the synthesis method of HBC-POSS organic-inorganic hybrid molecules containing a plurality of POSS can be carried out according to R₇Different groups adopt different synthetic strategies:

one synthetic strategy is: when R is₇When all the radicals are saturated covalent bonds, the R is partially led out from HBC₇And then connects the POSS. The method comprises the following specific steps:

1-1) to

As a substrate, by Co₂(CO)₈Preparing an HBC precursor with a structure shown in a formula (1) by catalytic trimerization of alkyne;

wherein at least two of the six R's are

The remainder being alkyl or alkoxy, R₇Is an alkylene group.

1-2) oxidizing the compound of formula (1) to prepare an HBC compound of formula (2);

preferably, ferric trichloride is used as an oxidizing agent in the step 1-2).

1-3) preparation of HBC compound represented by the formula (2)

Hydrolyzed and then reacted with POSS-OH or POSS-NH represented by the formula (3)₂Esterification or amidation reaction to preparePreparing the target product of the formula I.

In the formula (3), X is O or NH, n is an integer of 1-6, R₈To R₁₄The same as formula II.

Another synthetic strategy is: when R is₇In the case of unsaturated covalent bond, R is led out from POSS part₇And then subsequently connected to the HBC. The method comprises the following specific steps:

2-1) POSS-OH or POSS-NH represented by the formula (3)₂Carrying out esterification or amidation reaction with fatty acid with terminal alkynyl or terminal alkenyl to prepare POSS shown in formula (4);

wherein X is O or NH, n is an integer of 1-6, m is an integer of 1-18, R₈To R₁₄The same as formula II.

2-2) carrying out iodination reaction on hexaphenyl benzene shown in the formula (5) to generate hexaiodo-hexaphenyl benzene shown in the formula (6), wherein 0-4 iodides react with alkyl or alkoxy to obtain partially iodinated hexaphenyl benzene; in this case, the oxidation can be directly carried out to obtain iodo-hexabenzocoronene, or other substituent (such as aryl such as phenyl) is introduced through surplus iodine, then iodo reaction is carried out on the introduced other substituent to introduce an iodine group, and then oxidation is carried out to obtain iodo-hexabenzocoronene containing other substituent:

preferably, hexaiodohexaphenyl benzene is oxidized by ferric trichloride to prepare hexaiodohexabenzocoronene.

2-3) carrying out sonogashira or suzuki reaction on the POSS prepared in the step 2-1) and the iodo HBC prepared in the step 2-2) to obtain the compound of the formula I.

The invention also aims to protect the synthesis method of the HBC-POSS molecule, a method for obtaining the ordered structure of the HBC-POSS molecule and application of the HBC-POSS molecule in obtaining the nano template after etching the ordered structure by using oxygen plasma.

The HBC-POSS provided by the invention can be used for self-assembly of ordered structures to obtain hexagonal, lamellar and other arrangements with the size of a few nanometers, and is usually in a thin film form. The self-assembly method comprises the following steps: for the HBC-POSS, firstly, a Differential Scanning Calorimetry (DSC) is used for testing at a rate of 1-40K/min in a nitrogen atmosphere, and the phase transition temperature of each sample is confirmed. And then, after each sample (generally in a thin film state) is subjected to treatment of raising the temperature to be higher than the phase transition temperature and then lowering the temperature to room temperature at the speed of 0.1-10 ℃/min (preferably 1 ℃/min), a small-angle X-ray scattering (SAXS) test and a Transmission Electron Microscope (TEM) characterization are carried out, and the type and the size of the self-assembled structure are confirmed. For the appropriate structure, it is oxygen plasma etched to form the nano-template.

Compared with the prior art, the invention has the advantages that:

1) HBC-POSS organic-inorganic hybrid molecules with accurate molecular weight and chemical structure are used for self-assembly, so that the problem of polymer molecular weight dispersity is avoided;

2) the scale of the ordered structure formed by the HBC-POSS is below 10nm, and is smaller than that of the ordered structure formed by a common block copolymer;

3) the HBC-POSS in the invention is used for oxygen plasma etching, so that a nano template with the size of less than 10nm can be obtained, and a new possibility is provided for solving the bottleneck of the size of the chip nano template.

Drawings

FIG. 1 is a SAXS diagram of several HBC-POSS molecules prepared in example 1 and example 2.

Fig. 2 is a TEM image of HBC-6POSS (X ═ NH) prepared in example 2.

Detailed Description

The invention will be further described by means of specific embodiments in conjunction with the accompanying drawings.

Example 1 synthesis of HBC-2POSS (formula Ia, X ═ O, NH)

Step 1: synthesis of HBC precursor

A250 mL three-necked flask was charged with 2.5g of 1, 2-bis (4- (2-hexyldecyl) phenyl) acetylene, 1.25g of methyl 4, 4' -undecanoate diphenylacetylene, and 300mg of dicobalt octacarbonyl, and a reflux condenser was added. Then, under the nitrogen atmosphere, 80mL of ultra-dry 1, 4-dioxane was added, and the mixture was refluxed at 110 ℃ for 48 hours. After the reaction was completed, the solvent was directly spin-dried, and the product was obtained in an amount of 1.02g by column separation (petroleum ether: dichloromethane: 6: 1) with a yield of 30%.

Step 2: synthesis of HBC

In a 100mL round bottom flask was added 300mg of the HBC precursor synthesized in step 1, followed by addition of 50mL of dry dichloromethane under nitrogen and bubbling for 15 min. A solution of ferric trichloride (480mg) in nitromethane (2mL) was added with continuous bubbling, and the mixture was stirred at room temperature for 1 hour. After the reaction was completed, the reaction solution was quenched by adding methanol, and then the reaction solution was dropped into a large amount of methanol, and the precipitate was filtered. The precipitate was subjected to column separation using dichloromethane as an eluent to obtain 240mg of a yellow product in 80% yield.

And step 3: synthesis of HBC-2POSS

In a three-necked flask, 200mg of HBC and 250mg of potassium hydroxide (KOH) were charged, and a reflux condenser tube was added. Then, 100mL of tetrahydrofuran, 4mL of methanol and 1mL of water were added under a nitrogen atmosphere, and the mixture was refluxed at 70 ℃ for 24 hours. After the reaction, the reaction mixture was cooled to room temperature, and 10% hydrochloric acid was added to adjust the reaction mixture to acidic. The organic phase was extracted with dichloromethane and washed with water and dried over anhydrous sodium sulfate. The reaction was filtered, spin dried and then chromatographed on a column with dichloromethane/methanol (v/v ═ 10/1) to give the product as a yellow color. The product is mixed with POSS-OH or POSS-NH₂190mg, 4-Dimethylaminopyridine (DMAP)8mg, N, N' -Diisopropylcarbodiimide (DIC)41mg were addedA50 mL round-bottom flask was charged with 20mL dry dichloromethane and stirred at room temperature for 24 h. After completion of the reaction, the reaction solution was spin-dried and subjected to column separation using petroleum ether/dichloromethane (v/v. 4/1) to obtain 160mg of a yellow product with a yield of 55%.

Example 2 Synthesis of HBC-6POSS (formula Ib)

Step 1: synthesis of hexaiodohexaphenylbenzene

0.598g of hexaphenylbenzene, [ bis (trifluoroacetoxy) iodo ] benzene (1.62g) and iodine (0.945g) were added under nitrogen, followed by 50mL of dried dichloromethane, and stirred at room temperature for 17h in the absence of light. Adding n-hexane to quench the reaction, filtering, and washing filter residue with n-hexane. Then, the filter residue is dissolved in chloroform, washed with a sodium sulfite solution and a saturated sodium chloride solution in sequence, and dried with sodium sulfate. The solvent was spin-dried, and then recrystallized from a chloroform-n-hexane mixed solvent to obtain 1.1g of a white solid.

Step 2: synthesis of p-trisilyl phenyl hexaphenyl benzene

To a three-necked flask were added hexaiodohexaphenylbenzene 0.332g, p-trimethylsilylphenylboronic acid 0.585g, potassium carbonate 1.39g, and palladium tetrakistriphenylphosphine 70 mg. Then, 20mL of toluene and 10mL of water were added under a nitrogen atmosphere. Refluxing at 100 deg.C for 24 h. After the reaction was completed, the mixture was separated, extracted with dichloromethane, and the organic phase was dried over anhydrous sodium sulfate. Then, the column separation was carried out using a petroleum ether/methylene chloride (v/v. 3/1) eluent, whereby 380mg of a white product was obtained.

And step 3: synthesis of p-iodophenyl hexaphenyl benzene

To a 250mL round bottom flask was added 380mg of p-trisilylphenylhexaphenylbenzene, followed by addition of 150mL of chloroform under nitrogen, followed by slow addition of 3.5mL of iodine chloride solution. After 2h of reaction, the reaction was quenched by addition of 10% sodium sulfite solution. Then, the organic phase was washed with water 3 times, dried over anhydrous sodium sulfate, filtered, and the solvent was spun off. The solid was precipitated by dropping a dichloromethane solution into a large amount of methanol, filtered, and the filter cake was collected to obtain 413mg of a white solid.

And 4, step 4: synthesis of HBC

In a 500mL round bottom flask was added p-iodophenyl hexaphenylbenzene 400mg, followed by addition of dichloromethane 240mL and carbon disulfide 120mL under nitrogen, and bubbling was carried out for 15 min. Ferric trichloride (4.10g) in nitromethane (15mL) was added and the reaction was allowed to proceed for 4h with continued bubbling. After the reaction is finished, pouring the reaction solution into a large amount of methanol, filtering, and continuously washing filter residues with methanol until the filtrate is colorless. A total of 400mg of black solid was collected.

And 5: synthesis of POSS (X ═ O, NH)

Adding POSS-OH or POSS-NH into a 50mL round-bottom flask₂600mg, 185mg of 1-alkyne-undecanoic acid, DMAP50mg, DIC 0.21mL, then 15mL of dichloromethane were added and dissolved, stirring was carried out at room temperature for 24 h. After the reaction, the reaction solution was spin-dried and column-separated to obtain 660mg of the product.

Step 6: synthesis of HBC-6POSS (formula Ib, X ═ O, NH)

90mg of HBC obtained in the step 4, 600mg of POSS obtained in the step 5, 26mg of palladium tetratriphenylphosphine and 5mg of cuprous iodide are added into a 25mLSchlek bottle, 10mL of piperidine is added as a solvent, and the mixture is frozen and pumped for 3 times and reacted for 48 hours at 50 ℃. After the reaction was completed, the reaction solution was dropped into a large amount of methanol, filtered, and the filter cake was subjected to column separation using dichloromethane as an eluent to obtain 210mg of a yellow product (compound of formula Ib).

Example 4 obtaining of ordered HBC-POSS Structure

For the samples of formula Ib, a Differential Scanning Calorimeter (DSC) was first used to perform an increasing and decreasing temperature test at a rate of 10K/min in a nitrogen atmosphere to confirm the phase transition temperature of each sample. Then, each sample (body and film) is processed by raising the temperature to a higher temperature and then lowering the temperature to room temperature, so as to obtain a long-range ordered monoclinic or hexagonal columnar phase structure at room temperature. Then, a small angle X-ray scattering (SAXS) test is carried out, the test result is shown in figure 1, and it can be seen that a monoclinic long-range ordered structure is formed for HBC-2POSS, and the POSS content is increased to 6POSS, namely HBC-6POSS, and a hexagonal columnar phase structure is formed; for the sample HBC-6POSS (X ═ NH), the sections were embedded in resin after heat treatment and then characterized by Transmission Electron Microscopy (TEM), and as a result, it can be seen from fig. 2 that the morphology of the sample did form a hexagonal columnar phase structure. The SAXS and TEM technologies are utilized to confirm that the ordered structure is a monoclinic or hexagonal columnar phase structure and the size of the ordered structure is below 10 nm.

Example 5, obtaining of Nanomaode with size of 10nm or less

For the sample of formula Ib, it can form structures with dimensions below 10nm according to its SAXS and TEM results, and thus, can be used for the preparation of nano-templates. Taking HBC-6POSS-CONH as an example for explanation, firstly weighing 1mg of sample, dissolving in 1mL of toluene, and preparing into 1mg/mL of solution; then spin-coating on the silicon wafer by using a spin-coating instrument to obtain a film of a sample, and placing the film at a higher temperature for thermal annealing; and observing the processed film by using AFM (atomic force microscopy), finding that the processed film forms a large-area ordered structure, and finally performing oxygen plasma etching on the film sample to obtain the nano template with the period size of less than 10 nm.

Claims (4)

1. A method of preparing an organic-inorganic hybrid molecule having a hexabenzocoronene-centered structure as shown in formula I:

in the formula I, R₁、R₂、R₃、R₄、R₅And R₆The two groups are the same or different, at least two of the groups are groups with the ends of cage-type silsesquioxane shown as the formula II, and the rest are alkyl or alkoxy;

in the formula II, R₇Is a chain group containing alkylene, alkenylene, alkynylene and/or arylene, and the wavy line represents a connecting bond with the hexabenzocoronene core; r₈、R₉、R₁₀、R₁₁、R₁₂、R₁₃And R₁₄The same or different, each independently is alkyl, alkoxy, cycloalkyl, alkenyl, alkynyl or aryl; x represents O or NH; n is an integer of 1-6;

wherein R is₇Contains unsaturated covalent bond, and the R is led out from the cage-type silsesquioxane group₇Then connecting to the hexabenzocoronene core, and the specific steps are as follows:

2-1) POSS-OH or POSS-NH represented by the formula (3)₂Carrying out esterification or amidation reaction with fatty acid with terminal alkynyl or terminal alkenyl to prepare the cage-type silsesquioxane group shown as the formula (4);

wherein X is O or NH, n is an integer of 1-6, m is an integer of 1-18, R₈To R₁₄As described above;

2-2) carrying out iodination reaction on hexaphenyl benzene shown in the formula (5) to generate hexaiodo-hexaphenyl benzene shown in the formula (6), wherein 0-4 iodides react with alkyl or alkoxy to obtain partially iodinated hexaphenyl benzene; then, directly oxidizing to obtain iodo-hexabenzocoronene, or introducing other substituent groups through surplus iodine, then performing iodination reaction on the introduced other substituent groups to introduce iodine groups, and then oxidizing to obtain iodo-hexabenzocoronene containing other substituent groups;

2-3) carrying out sonogashira or suzuki reaction on the cage-type silsesquioxane group prepared in the step 2-1) and the iodo-hexabenzocoronene prepared in the step 2-2) to obtain the organic-inorganic hybrid molecule.

2. The method of claim 1, wherein R in formula I is₁、R₂、R₃、R₄、R₅And R₆When 1-4 of the alkyl groups are alkyl groups, the alkyl groups are C13-C30 straight chain or branched chain alkyl groups; when R in formula I₁、R₂、R₃、R₄、R₅And R₆When 1 to 4 of the alkoxy groups are alkoxy groups, the alkoxy groups are C1-C30 straight-chain or branched alkoxy groups.

3. The method of claim 1, wherein R in formula II₇Is a chain group containing alkylene, alkenylene, alkynylene and/or arylene of C1-C20.

4. The method of claim 1, wherein R is₈、R₉、R₁₀、R₁₁、R₁₂、R₁₃And R₁₄Is alkyl, cycloalkyl, aryl or alkoxy of C1-C18.

Images