KR20090035936A - The formative method of functional nano pattern - Google Patents

Abstract

A method for forming functional nano pattern is provided to directly apply specific functions to 3D surface-modified nano pattern. A method for forming functional nano pattern is characterized by activating surface of nano structure having nano-sized protrusions in order to be covalently bonded with organic materials and contacting a stamp(100) coated with organic materials to the nano structure surface so as to immobilize the organic materials by the nano-sized protrusions. A substrate(102) having nano structure with nano-sized protrusions is transferred by a nano imprint method using intaglio structure of anodized aluminum oxide. The method for activating the surface of the substrate is processed through a plasma treatment. The plasma treatment represents oxygen plasma or ammonia plasma.

Description

The formative method of functional nano pattern

The present invention relates to a method of forming a functional nanopattern, and more particularly, after forming anodized aluminum into a nanostructured surface having a nanometer-sized protrusion, nanoimprinting it on a plastic substrate, and then ammonia plasma method. The method of the present invention relates to a method of selectively immobilizing organic materials on protruding portions of nanostructures by activating a surface and pressing planar stamps coated with organic molecules such as proteins onto the surface of the nanostructures.

Contact printing technology, which transfers patterns by directly contacting the stamp to the substrate, eliminates the use of expensive equipment such as photomasks and steppers, or toxic compounds, but in a simple way at the micrometer level. There is an advantage that the pattern can be effectively produced.

The stamp is produced by hardening an elastomer by mixing a monomer or an initial polymer of a polydimethylsiloxane (PDMS), which is mainly a liquid, with a curing agent and pouring it into a reversed patterned master mold. In addition to PDMS, there are elastic materials such as polyurethane (PU) and Novolac, but PDMS is not only a good elastomer, but also has high chemical stability, and is suitable for plasma treatment or formation of an appropriate self-assembled organic thin film after plasma treatment. It is possible to modify the surface through the method, and in particular, since it is a porous material, air generated by the pressure applied during stepping can be properly released to the rear and side, and the absorption and discharge of the material applied to the surface can be easily performed. It is known as a very suitable material for substrate transfer. However, due to the nature of the elastic material itself, there is a certain limit to the resolution of the stamp that can be manufactured. Recently, attempts to overcome this limitation by using hard PDMS have been made at the academic level. Even the surface with the degree of curvature may cause new problems such as the loss of the uniform contact characteristics that could be printed without difficulty.

The fine pattern fabrication technology has been diversified in the past decades with the development of next generation lithography (NGL) to replace it, thanks to the enormous economic ripple effect of photolithography used in electronic device manufacturing. As a result, using a scanning probe microscope (SPM) method, nanoimprinting lithography (NIL), micro contact printing (micro contact printing) technology, such as relatively simple equipment and processes are satisfactory Useful techniques for producing patterns have been secured, and recently, various researches using them have been continued.

Such changes in the surrounding environment can be used for application research or technology development by using how easily, at a large area, and how large a pattern of a suitable resolution can be produced in a conventional situation in which the resolution of a fine pattern is competitive. Whether it exists or not, the axis of technology development is shifted.

In particular, as nanometer-sized patterns can be manufactured further from micrometers, such a pattern making technique is most fundamentally required in the so-called nano bio research, which manufactures nanometer-level structures and performs various biotechnological experiments thereon. This is a key requirement. In addition, immobilizing various biotechnologically active biomolecules such as proteins on the fabricated pattern is expected not only for the development of biosensor-based diagnostic kits, but also for the study of cell behavior and application to tissue engineering. The range of ramifications is very wide. In most cases, however, biomolecule immobilization techniques still apply a cocktail containing extra cellular matrix (ECM) proteins to glass or some plastic plates, or use a pipette to roughen an immunologically mated material. It is made of nonselective and nonspecific methods in terms of its quantitative and design aspects such as dipping and sticking, and there are hardly any examples of introducing molecular-level design technology using fine chemistry.

The present invention provides a technique for patterning plastic plates using nanoimprint technology and selectively immobilizing various sensing materials including proteins, which are biomolecules, on the surface of the three-dimensional nanostructures thus made.

The present invention for this purpose is to enable the surface of the organic structure to covalently bond the organic molecules to the substrate having a nanostructured surface having a nanometer-sized protrusion, and contact the nano-structured surface with the stamp coated with the organic molecules It is a method of forming a functional nano pattern characterized in that the organic material is fixed by the protruding portion. Substrate having a nanostructured surface having a nanometer-sized protrusion is preferably transferred to the anodized aluminum anodized structure of the structure by a nanoimprint method, the surface activation method on the substrate may be carried out by plasma treatment. . The surface activation method on the substrate may be made by selecting from the group consisting of an amine group, a hydroxyl group, a carboxyl group, an aldehyde group and a silane group on the substrate, the substrate is made of polystyrene, polymethylmethacrylate (polymethylmethacrylate, PMMA) It may be selected from the group consisting of polyethylene terephthalate (PET), and polycarbonate. To summarize this step by step, anodizing aluminum to form a protruding nanostructure shape; Nanoimprinting a plastic substrate using the anodized aluminum as a mold; Plasma treating the plastic substrate to impart functionality to the surface; Inking an organic compound that is bondable to the surface of the plastic substrate on a stamp; The method of forming a functional nanopattern may include fixing the organic material by contacting the stamp with a plastic substrate.

In addition to the nanoimprint method using anodized aluminum, the concept of contact printing is used in reverse, and flat stamps are used to easily and cheaply mass-produce large-area organic nanopatterns.

In addition, while the existing contact printing technology provides a selective modification technique on a planar substrate, and mainly for the purpose of patterning the substrate through the etching of the substrate, etc., the present invention selects a nano-pattern structured three-dimensional already It has a differentiated methodology and purpose that it is possible to directly impart specific functionality by surface modification.

Hereinafter, the present invention will be described in more detail, and in describing the present invention, detailed descriptions of related well-known technologies or configurations are omitted in order not to obscure the subject matter of the present invention.

The present invention transfers a pattern onto a flat plate such as polystyrene (PS) using a nanoimprint technique using a mold made of anodized aluminum oxide (AAO), and ammonia plasma treatment of the pattern surface to form an amine function. The group was introduced, and an example of inducing selective immobilization by contacting plated PDMS coated with Fibronectin, which is one of the extracellular matrix proteins, was performed.

AAO is a surface treatment technology that can produce a solid and transparent oxide film on a surface of aluminum by simple electrochemical reaction. It is used for a wide range of decorative, architectural coatings, home appliances, sporting goods, defense products, and mechanical parts. It is already widely used industrially, etc. In particular, the film to be formed has a certain structure that can be controlled at the nanometer level according to the manufacturing conditions.

On the other hand, nanoimprint is a technology that transfers the intaglio pattern by uniformly pressing it with a strong pressure on the target substrate by using a mold having a rigid pattern, which has the advantage of making a plurality of transfer patterns by a simple method. In addition, plastic plates such as PS, polymethyl methacrylate (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) have polymer plates whose glass transition temperature exceeds room temperature. For example, the nano-patterns fabricated on these substrates by combining AAO and NIL form well-controlled patterns and patterns with a well-controlled size and shape, and thus are very suitable nanostructures to effectively show the results of the present invention.

Plastic substrates such as PS are carbon-based high molecular substances. When plasma treatment with oxygen or ammonia is applied, chemical functional groups such as hydroxyl group (-OH) and amine group (-NHx) are used. Can be introduced to the surface. The chemical functional groups introduced on the surface are chemically covalently bonded to organic material molecules including chemical functional groups such as carboxylic acid (-COOH), aldehyde (aldehyde, -COH), epoxy, silane, etc. The surface can be strongly immobilized, which is very useful. Alternatively, these may be introduced directly. By utilizing the high reactivity of the plasma it is possible to conveniently functionalize the surface of the non-reactive polymer material. This mechanism involves a non-polymerized gas plasma to generate reactive molecular fragments that covalently bond to the surface of the reactive material during the plasma reaction. The process can be performed at low temperatures because there is no need to heat it externally to break the chemical bond. Each plasma form is used depending on the group needed to have the functional groups that require the surface of the polymer. For example, an N ₂ H ₄ RF plasma may be used to introduce an amine group, and a hydroxyl group or the like may be introduced using an Oxygen RF plasma.

 1 is a schematic diagram illustrating a schematic process of the present invention for selectively immobilizing an organic material on a patterned surface. A chemical functional group is introduced to the patterned plastic substrate 102, and an inking material 101 capable of bonding to the chemical functional group is coated on the stamp 100 to contact the inductive material to induce immobilization.

5 shows an example of inducing selective modification by another method using the technical core of the present invention. The process of FIG. 5 replaces the substrate 102 with the patterned surface with a surface 702 previously modified with another material, but still follows the concept of reverse contact printing, which is a technical core of the present invention. The inking material 701a is shown to be selectively coupled (701b).

Hereinafter, the present invention will be described through embodiments of the present invention.

<Production of mold made of AAO>

Aluminum anodization techniques are used to fabricate microstructures that are iterative and size controlled at the nanometer level. First, the aluminum substrate is placed in a 25% perchloric acid ethanol solution, and a potential of 20 V is applied for about 5 minutes, and the temperature is maintained at 7 ° C. After anodizing at 0.1 ° C solution for 10 hours at 0 ° C, 193V, and immersed for 12 hours while maintaining 65 ° C in chromic acid solution (chromic oxide 9g + 20.3ml phosphoric acid + distilled water = 500ml). Again anodize at 0 ° C and 193V for 5 hours in 0.1M phosphate solution. After this, maintain the 30 ° C in phosphoric acid solution (phosphate 5.765g + distilled water = 500ml) and immerse for 2 and a half hours or four hours to complete the mold form.

The scanning electron micrograph of the AAO mold produced by such a process is shown in FIG.

<Transfer of Pattern to Plastic Substrate>

Using the above-described microstructure as a mold, the intaglio pattern of the pattern is transferred to the plastic substrate using a nanoimprint method. The plastic substrate used polystyrene (PS). This method means that when the polymer film is spin coated onto the mold, the polymer layer can be simply transferred to the plastic plate (polymer film) by the spin coating method in the pattern of the mold surface. It is simply a method in which a polymer film-coated mold is simply placed on a substrate and heated to a glass transition temperature to transfer the pattern to the plastic. The main key to this method is that the mold must have a lower surface energy than the substrate, the polymer film must have high adhesion to the substrate, and the film must be separated from the mold without defects.

Plasma treatment of plastic substrates

Ammonia plasma (N ₂ H ₄ RF plasma) is treated to the PS pattern prepared above to introduce amine chemical functional groups to the pattern surface. By utilizing the high reactivity of the plasma it is possible to conveniently functionalize the surface of the non-reactive polymer material.

3A is an XPS analysis result of nitrogen element on the surface of the pattern thus produced. It can be seen that most of them are in the form of primary amines and some exist in ionic form. 3B is a scanning micrograph of the surface of the fabricated pattern.

<Stamp Making>

PDMS is poured onto a quartz wafer to produce a flat stamp. Produced above

Inking the PDMS material capable of chemically covalent bonding with the surface of the plastic pattern having the aminated surface prepared above. In the present invention, 50 μg / mL of the fibronectin solution was prepared and inked soaked to the bottom of the flat side of the prepared PDMS stamp. In addition, fibronectin inking was performed on non-selected surface-modified stamps of the general method.

<Fixation>

The inked PDMS fabricated above was in contact with the surface of the PS substrate to induce immobilization through chemical covalent bonds.

Figure 4a shows a scanning micrograph of a micropattern in which the organic material fibronectin is selectively immobilized only at the top of the pattern by this process, Figure 4b is a scanning micrograph of the result of contacting the fibronectin in the form of a solution on the pattern surface to be. In contrast to FIG. 4A, it can be seen that immobilization proceeded non-selectively evenly over the entire surface of the pattern.

As described above, the technical configuration of the present invention may be embodied in other specific forms while maintaining the concept of the technical core of the present invention or essential accompanying conditions, that is, simultaneous use of the nanoimprint method and reverse contact printing. It will be appreciated that the embodiments described herein are to be construed as illustrative in all respects and should not be construed as limiting.

Therefore, the specific scope of the present invention is defined by the above-described claims rather than the embodiments described above, and all changes and modifications derived from the meaning and scope of the claims and equivalent concepts thereof may be used. It should be interpreted as including the scope.

1 is a cross-sectional view illustrating the concept of reverse contact printing.

Figure 2 is a SEM result photograph of the fine pattern formed by the aluminum anodization technique.

Figure 3a is an XPS result of the surface obtained after ammonia plasma treatment of the fine pattern transferred on the PS substrate.

Figure 3b is a SEM photograph of the fine pattern treated with ammonia plasma.

4A is a SEM result photograph of a fine pattern selectively surface modified using an embodiment of the present invention.

Figure 4b is a SEM result photograph of the non-selectively surface modified fine pattern in contrast with the embodiment of the present invention.

5A is a process cross-sectional view illustrating various selective modification methods utilizing the technical core of the present invention.

FIG. 5B is a cross-sectional view of the selectively modified pattern produced by the process of FIG. 5A. FIG.

Claims (8)

The organic material is activated by covalent bonding of organic molecules to a substrate having a nanostructured surface having a nanometer-sized protrusion, and the stamp coated with the organic molecules is brought into contact with the surface of the nanostructure to form an organic material by the protruding portion of the nanostructure. Method for forming a functional nanopattern, characterized in that for fixing. The method of claim 1, And a substrate having a nanostructured surface having a nanometer-sized protrusion, wherein the anodized aluminum anodized structure of the structure is transferred by a nanoimprint method. The method of claim 1, And the surface activation method on the substrate is carried out through a plasma treatment. 4. The method of claim 3, wherein the plasma treatment is oxygen plasma or ammonia plasma. The method according to any one of claims 1 to 4, The method for surface activation on the substrate is characterized in that it is selected from the group consisting of amine groups, hydroxyl groups, carboxyl groups, aldehyde groups and silane groups and introduced into the substrate. The method according to any one of claims 1 to 4, The substrate is selected from the group consisting of polystyrene, polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate. The method according to any one of claims 1 to 4, And said stamp uses PDMS or similar elastic material. Anodizing aluminum to form a nanostructure shape of a protruding shape; Nanoimprinting a plastic substrate using the anodized aluminum as a mold; Plasma treating the plastic substrate to impart functionality to the surface; Inking an organic compound that is bondable to the surface of the plastic substrate on a stamp; And contacting the stamp with a plastic substrate to fix the organic material.

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