KR100696254B1 - The patterning method of nanosized blockcopolymer micelle - Google Patents

Abstract

The present invention provides a method comprising: covering a block copolymer thin film spin-coated on a substrate with a flexible mold having a channel and conformally contacting the block copolymer; Injecting a polar solvent capable of dissolving the hydrophilic portion of the block copolymer micelle through the channel of the mold by capillary action to expose the hydrophilic portion to the outside; And it relates to a patterning method of the nano-size polymer micelle consisting of removing the mold.

 The present invention is capable of manipulating the hydrophilic and hydrophobic regions of a thin film in a nanoscale polymer micelle thin film with a desired pattern, in particular, a short process time, large area orientation, low manufacturing cost, and arbitrary pattern formation, Regardless of the pattern, there is an advantage in that selective adsorption of metal ions is possible.

Block copolymers, soft lithography, micelles, PDMS

Description

The patterning method of nanosized blockcopolymer micelle}

1 is a cross-sectional view of a nanoscale micelle thin film of a substrate and a block copolymer formed thereon.

2 is a perspective view illustrating a state in which a mold is conformally contacted on a polymer micelle thin film.

3 shows that the polar solvent is filled by capillary action into the channel of the mold.

Fig. 4 shows a cross-sectional view of the thin film portion B changed by contact with the solvent after mold removal and the thin film portion A which is not in contact with the solvent and does not change.

 Fig. 5 is a cross-sectional view showing a state in which metal ions are adsorbed onto the water-soluble polymer thin film portion B exposed to the surface by a solvent.

6 is a SEM photograph showing the surface state of a thin film patterned with ethanol as a result of the embodiment.

7 is a SEM photograph showing the result of bonding metal ions to the water-soluble polymer thin film portion B exposed to the surface by ethanol as a result of the example.

** description of the main symbols in the drawings **

10: substrate

20: nano size block copolymer micelle thin film

21: hydrophobic polymer in the block copolymer

22: hydrophilic polymer in the block copolymer

23: Ionic material (eg metal ion)

30: Mold

31: channel

 The present invention relates to a method of patterning nano-sized block copolymer micelles. More specifically, the present invention relates to a method of patterning hydrophilic and hydrophobic regions by applying soft lithography technology used in the semiconductor field to nanoscale block copolymer micelle thin films.

Hereinafter will be described with respect to the related art for the understanding of the present invention.

Nanoscience suggests new physical, chemical and material phenomena and their applications. In order to realize, device and commercialize the characteristics and performances suggested by nanoscience from the field of analyzing and researching unique phenomena in the nano world, various kinds of nanomaterials proposed and researched by nanoscience, for example, carbon nanotubes With the development of carbon nanotubes, quantum dots, nanowires, etc., a frame, or nano-pattern, that enables the selective separation, arrangement and further array formation of the nanomaterials. (nanopattern) development is essential.

To date, several methods have been proposed to fabricate nanometer structures. Conventional patterning of nanomaterials can be largely divided into a top-down method and a bottom-up method.

Lithography has been the most frequently used top-down method. Specifically, the method may be classified into a method using UV, an X-ray, an interferrometric lithography method using a laser, and the like.

  The top-down method described above is a method made for the production of semiconductor processes, and has various limitations in producing nanometer-sized structures. For example, the nanometer-sized structure can be manufactured by the top-down method, but it is difficult to apply to mass production due to the problems of cost and process time, which is applied to only a limited field of research. to be.

An alternative proposed to overcome the limitation of the top-down method is a bottom-up method. The bottom-up method, commonly referred to as soft lithography, is a printing method. The desired material is adsorbed onto a stamp made of a flexible material and then transferred to a desired semiconductor substrate. The way to transfer.

The present invention is to develop a nano-size patterning method of the polymer material by applying a bottom-up approach applied in the semiconductor field to the polymer. Polymeric materials have recently been in the spotlight for their performance as well as their mechanical properties to traditional functions, such as conductivity, semiconductivity, and optical properties. Its role is becoming important at the border with science.

  More specifically, the present invention relates to the patterning of hydrophilic and hydrophobic regions of nanoscale micelle thin films of block copolymers among various polymers. A block copolymer is a kind of polymer material in which two or more polymers are connected to each other through covalent bonds. As the simplest structure, a diblock copolymer forms two polymers by connecting two polymers having different inclinations. At this time, due to the different material properties of the two polymers connected to each other, the phase separation occurs due to the change of temperature, and unlike the macrophase seen in a normal polymer blend, due to the physical limitations due to the intermediate covalent bonds. It is spatially microphase. In general, the domain size of the self-assembled block copolymer is 5 ~ 100 nm wide to enable the production of uniform nano patterns of various sizes. Block copolymers have the advantage of being able to form more diverse microstructures that are thermodynamically stable only by controlling the relative lengths of the two polymers. The difference in the relative lengths of the two polymers covalently linked to each other is the thermodynamic energy balance at the inter dividing materials surface (IDMS) that will share with the interfacial tension at the interface when the two polymers form microstructures through phase separation. Curvature by means of which the block copolymer has various microstructures. For example, lamellar, cylindrical and spherical structures are formed, and other three-dimensional discontinuous microstructures such as double gyroids can also be obtained.

  In particular, the term micelle, which is a form of the microstructure of the block copolymer of the present invention, is derived from the spherical structure seen in the surfactant. Surfactants are monomolecules of small molecular weight and having both hydrophilic and hydrophobic moieties. Hydrophilic moieties are generally called heads, while hydrophobic moieties usually consist of alkyl chains and are called tails. When these single molecules are above a certain concentration in the liquid, they form nano-scale aggregates to stabilize their energy. This is called micelles.

  The micelle structure can easily dissolve materials that are difficult to dissolve with common organic solvents and is useful for stabilizing colloids and nanoparticles. In addition, it is applied to a drug delivery system (drug delivery system) has been studied as a carrier that allows the drug to penetrate only a specific part inside the body. In particular, when the block copolymer micelle is applied to the production of nanoparticles, it is possible to synthesize the nanoparticles by the micelle structure. That is, by aligning the block copolymer micelles or adjusting their properties, the arrangement of the metal particles is possible only at any desired position.

Conventionally known methods for orienting spherical nanostructures, such as micelles, include a method of directly aligning micelles in a solution, a method of preparing a thin film, and then performing a patterning method.

First, the method using a liquid solution is to pattern the substrate itself to prepare the bend, and then the micelle solution is injected into the capillary phenomenon. The injected micelle solution forms a dense structure as the solvent evaporates, and the result is oriented in the dense structure only at its interface along the groove of the substrate. This method is called artificial epitaxy or graphoepitaxy, and can be applied not only to colloids but also to block copolymers and block copolymer micelles using artificially prepared substrates.

This method not only enables the orientation of a large area, but can also be manufactured at low cost and can reduce the processing time. However, since the structure is formed by evaporation of the solution, the density of the flexion is shown to be lowered, and the substrate must be able to be stably maintained with respect to the micelle solution. In addition, the need to use pre-patterned substrates makes them unsuitable for mass production.

The method using a block copolymer micelle thin film, on the other hand, is a method of increasing the possibility of mass production. In addition to manufacturing a compact structure through a simple process, it is possible to evenly disperse the metal particles and to form an arbitrary pattern through an electron beam applied from the outside. However, this method also requires a lot of processing time because of the use of an electron beam, which still has the disadvantage that it cannot be used for mass production. In addition, it has the disadvantage that it can be applied only to the pattern formation of one kind of metal particles.

In Table 1 below, the advantages and disadvantages of the conventional patterning method are analyzed.

 Table 1

 Patterning Method  Advantages  Disadvantages  Solution Patterning ○ Short process time ○ Large area orientation possible ○ Low production price ○ Only available on pre-pattern  Patterning Using Electron Beams ○ Any pattern can be formed ○ Pattern can be formed on flat plate ○ High density ○ long process time ○ high production price  Patterning using pre-patterns and block copolymers ○ Large area orientation possible ○ Adjustable defect according to pattern size ○ High density ○ Only on prepattern ○ Long processing time ○ High production price

 An object of the present invention is to overcome the problems of the conventional patterning method of nano-sized polymer micelles, short process time, arbitrary pattern formation, no pre-pattern, large area orientation To develop a hydrophilic and hydrophobic patterning method of the nano-size polymer micelle thin film is possible.

 The present invention to achieve the above object,

(a) conformally covering a block copolymer thin film spin-coated on a substrate with a flexible mold having a channel;

(b) injecting a polar solvent capable of dissolving the hydrophilic portion of the block copolymer micelle through the channel of the mold by capillary action to expose the hydrophilic portion to the outside; And

(C) provides a hydrophilic and hydrophobic patterning method of the nano-size polymer micelle thin film consisting of removing the mold.

Further, if necessary, after step (c), the hydrophilicity of the nano-sized polymer micelle thin film further comprises a step (step d) of adsorbing the polar material to the non-covalent electron pair of the hydrophilic component exposed to the outside. A hydrophobic patterning method is provided.

In the above, it provides a hydrophilic and hydrophobic patterning method of nano-sized polymer micelle thin film, characterized in that the polar solvent capable of melting the hydrophilic micelle central portion is ethanol.

In the above, the mold is provided with hydrophilic and hydrophobic patterning method of nano-sized polymer micelle thin film, characterized in that PDMS (P oly i D S M ethyl iloxane).

Provides a copolymerizable hydrophilic and hydrophobic patterning method of nano-sized polymer micelle thin film, it characterized in that the chain - in the block copolymer is a polystyrene (PS = PolyStylene) and P4VP [(V inyl- P yridine 4 ) P oly] .

In particular, it provides a hydrophilic and hydrophobic patterning method of the nano-size polymer micelle thin film, characterized in that the polar material used in the step (d) is a metal ion.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

First, an arbitrary polymer block copolymer on a substrate is spin-coated using a conventional method to form a thin film. As shown in FIG. 1, the polymer thin film 20 on the substrate 10 self-assembles nano-size micelles divided into hydrophilic 22 and hydrophobic 21 portions by microphase separation between hydrophilic and hydrophobic portions. Hydrophilic polymer portion 22 is inside the micelle, and hydrophobic polymer portion 21 is present on the top surface of the thin film and outside the micelle.

As shown in FIG. 2, the flexible mold 30 is covered on the nano-size micelle thin film 20 prepared above. Preferably the mold is characterized in that the PDMS (PolyDiMethylSiloxane). PDMS is widely used in soft lithography in the semiconductor field, and plays a role similar to a stamp. However, in the present invention, PDMS does not simply act as a stamp, but a patterned channel of PDMS itself. It differs from the prior art in that it provides a migration route for polar solvents through

Polar solvents, such as ethanol, present at one end of the channel are spontaneously filled to the opposite channel by capillary action. Such printing is referred to as "Solvent Capillary Contact Printing" (hereinafter abbreviated as "SCCP") as opposed to "Micro Contact Printing" used in the conventional semiconductor field. The solvent filled in the channel is removed by evaporation, and the evaporation rate of the solvent can be controlled at the required rate by adjusting the temperature.

The portion exposed to the polar solvent is exactly the same as the pattern and size of the channel. The reason is that the nano-sized polymer micelle thin film and the polymer such as PDMS can maintain so-called conformal contact so that the solvent does not flow to the outside of the channel (region A). Because there is.

After the patterning of the thin film surface is completed through the above processes, the mold is removed.

As a result of the above step, the central region 22 of the hydrophilic Maesel is expanded due to the polar solvent introduced in the region B, so that the spherical micelles are broken and the hydrophilic portion is exposed to the outside as shown in FIG. That is, by using the patterning method of the present invention, it is possible to manipulate (manupulation) in the form of the hydrophilicity and hydrophobicity coexist in a desired pattern in a desired portion of the nano-size polymer micelle thin film.

The modified block copolymer micelle thin film simultaneously shows hydrophilicity and hydrophobicity, and the confirmation can be understood as the degree of adsorption of water vapor. That is, the adsorption of water vapor selectively occurs in the hydrophilic B region, and the hydrophobic A region has a weak adsorption degree.

In the case of using the method of the present invention, a desired patterned nanoscale polymer micelle thin film can be prepared in a large amount in a short time compared with a method using a pre-pattterned substrate or an electron beam. Not only can it, there is an advantage that the manufacturing cost is also low.

In addition, if necessary, after removing the mold, the polar material may be adsorbed to the non-covalent electron pair of the hydrophilic component exposed to the outside. This is by using the ion adsorption capacity of the unshared electron pair in the hydrophilic polymer exposed to the outside, it can be adjusted to have the desired physical properties to the thin film by adsorbing various metal ions. 5 shows the adsorption of the polar material 23 in the hydrophilic region B. As shown in FIG.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the embodiments, and various modifications are possible within the scope of the present invention.

Example

P4VP [P oly (4 - V inyl P yridine)] of a hydrophilic polymer on a silicon wafer a thin film of mono-layer on the substrate by spin-coating of a block copolymer, PS (P oly S tyrene) was prepared from a hydrophobic polymer. Hydrophilic P4VP blocks were spherical in the lower surface of the thin film, and the hexagonal arrangement was confirmed by AFM (Atomic Force Microscopy) and TEM (Transmission Electron Microscopy).

As a result of analyzing the water adsorption experiment performed on the block copolymer formed on the silicon wafer with an optical microscope, it was confirmed that the adsorption of water was very irregular, and the adsorption capacity was also very poor.

Based on these facts, surface properties and microstructures were controlled by patterning on the block copolymer thin film. The pattern used was PDMS, which is widely used as a stamp of soft lithography. The pattern was linear, and the cycles were 2 μm (A region) and 3 μm (B region).

First, prior to this experiment, the effects of the plasma-treated PDMS mold and the plasma-treated PDMS mold were analyzed. This is because, when the plasma effect affects the shape change of the thin film, it is unknown why the shape change of the thin film is caused. First, the effect of only the conformal contact was measured when the plasma was not treated. There was no change in the overall shape and microstructure of the thin film. Similarly, the microstructure of the thin film was not changed by the conformal contact of the plasma-treated PDMS. Through this, the effect of the plasma-treated stamp was irrelevant to the microstructure of the thin film, and the overall block copolymer thin film after the contact was also maintained undamaged and stable. Only the PDMS pattern with better adsorption force was buried on the thin film. It was analyzed that these factors affected only the selective region of the solvent and resulted in the protection of the part in contact with the pattern.

After the above plasma preliminary experiment, in order to pattern the block copolymer micelle thin film by micro size unit using PDMS pattern, a printing method using a capillary phenomenon using ethanol as a polar solvent was applied (Solvent Capillary Contact Printing, SCCP) method. It was.

 6 is an SEM result of the actual polymer thin film prepared in the above embodiment. The enlarged left image is a region (region A) protected by the PDMS pattern, and the right side shows a region (region B) whose surface shape is changed by the solution. That is, the changed area exposed to the solution has holes and exposed inside to be hydrophilic, whereas the area protected by PDMS is hydrophobic and still has hydrophobicity without losing its initial form.

FIG. 7 is an SEM result obtained by injection-adsorption of metal ions 23 on the unshared electron pair of the portion B (P4VP), which shows the hydrophilicity of the patterned polymer micelle thin film. As shown in the SEM results, the adsorption of metal ions can be patterned in microns, and this method can be applied to the adsorption of metal nanoparticles in block copolymer micelles.

As described above, the present invention can apply soft lithography to nano-sized polymer micelle thin films, so that the water-soluble and non-aqueous groups of the thin films can be manipulated in a desired pattern, in particular, short process time, large area orientation, low Production costs, arbitrary patterns can be formed, regardless of the pattern of the substrate, there is an advantage that the selective adsorption of metal ions is possible.

Claims (6)

 Conformally covering the block copolymer thin film spin-coated on a substrate with a flexible mold having channels; Injecting ethanol in a capillary action as a polar solvent capable of dissolving the hydrophilic portion of the block copolymer micelle through the channel of the mold to expose the hydrophilic portion to the outside; And removing the mold. 10. The method of claim 1, wherein the mold comprises removing the mold. delete Claim 1 wherein in, nanoscale hydrophilic and hydrophobic patterning method of a thin film polymer micelle, characterized in that the mold is a PDMS (P oly i D S M ethyl iloxane). In claim 1, wherein the block copolymer is a polystyrene (PS = PolyStylene) and P4VP [P oly (4 - V inyl- P yridine)] block copolymer hydrophilic and hydrophobic pattern of the nano-sized micelle polymer thin film, characterized in that the chain of fastening method . The method of claim 1, further comprising, after removal of the mold, adsorbing a polar material to an unshared electron pair of an externally exposed hydrophilic component. 6. The method of claim 5, wherein the polar material is a metal ion. 7.

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