KR101145867B1 - Method of forming nanostructures on a substrate by direct transfer of nanostructure with Spin-on glass - Google Patents

Abstract

The present invention relates to a method of forming a nanopattern using SOG (Spin-on Glass), and more particularly, to a method of forming a nanopattern using SOG (Spin-on Glass) And transferring the nanoparticles onto a substrate only by a pressurizing process to form a nanopattern. According to the present invention, if only the master mold is prepared, the SOG nano pattern having the same shape as the master mold can be transferred to the substrate by a simple pressing process without the need of an adhesive layer, ultraviolet rays, heat treatment, etc., A nano pattern can be formed on a substrate at low cost. Also, through a simple process and annealed to produce a SiO ₂ nano-pattern, since it is possible to easily even on a substrate surface a SOG nanostructure transfer because PDMS PVA resin or resin mold is flexible, can be easily applied to the highly efficient optoelectronic devices.

SOG, PDMS, h-PDMS, PVA, nanopattern

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming nanostructures on a substrate using a spin-on glass (SOG)

The present invention relates to a method of forming a nanopattern using SOG (Spin-on Glass), and more particularly, to a method of forming a nanopattern using SOG (Spin-on Glass) And then transferring the resultant to a substrate only by a pressurizing process to form a nanopattern.

Spin-on glass (SOG) is a composite material of organic and inorganic materials with a mixed cage-network structure and can be converted to SiO ₂ by annealing at a temperature of 400 ° C or higher. This material can be fabricated on various substrates through simple processes such as spin-coating, and has a transmittance of over 90% in the visible light range. Therefore, it can be applied to various fields such as nanobio, semiconductor, and optoelectronic device technology. It is a substance expected to be applied. Recent advances in nanotechnology have led to the development of technologies that improve specific functionality through various nano shapes such as lotus effect, shark skin effect, and moth eye effect. SOG materials are used as resists in various lithography techniques and have excellent moldability for nanometer-sized microstructures. Therefore, functional nanostructures can be fabricated and applied to various devices to improve device efficiency. do. Currently developed SOG nanopatterning technologies include e-beam lithography, photolithography, room temperature nanoimprint lithography, thermal curing nanoimprint lithography, and the like. .

Since e-beam lithography and photo lithography techniques have very low productivity of nanopatterns and room temperature nanoimprint lithography requires very high pressures above 100 atmospheres, There is a drawback that the master mold of the mold is susceptible to damage. In addition, thermal curing nanoimprint lithography can be performed at relatively low temperatures and pressures, but defects such as capillary bridges are caused by the solvent gas generated during the imprinting process So that the gas can easily escape to the outside. The SOG nano patterning technology developed so far has various problems as described above. Therefore, there is a need for a nano patterning technique that can solve such problems.

It is an object of the present invention to provide a nano patterning method which can solve low productivity, difficulty, and high cost of conventional nano patterning technology.

The present invention provides a method for directly transferring a nano pattern on a substrate using SOG so that the nano pattern can be easily implemented on a substrate.

Preparing a mold having nanopatterns on at least one resin selected from the group consisting of PDMS (polydimethyl siloxane), h-PDMS, and PVA (polyvinyl acetate);

Coating a spin-on glass (SOG) layer on the resin mold; And

Stacking the resin mold having the SOG layer formed thereon so that the upper surface of the substrate and the SOG forming surface meet and transferring the SOG layer onto a substrate; And

And removing the resin mold.

According to one embodiment, the step of coating a spin-on glass (SOG) layer on the resin mold may be performed by spin coating SOG in a liquid phase containing 5 to 25 wt% of SOG at 500 to 7000 rpm for 10 to 30 seconds And forming a film with a thickness of 50 to 1000 nm.

According to one embodiment, the SOG is selected from the group consisting of silicate, siloxane, methyl silsequioxane (MSQ), hydrogen silsequioxane (HSQ), perhydropolysilazane perhydropolysilazane ((SiH ₂ NH) n)), polysilazane, and mixtures thereof.

According to one embodiment, the liquid SOG is selected from the group consisting of methyl isobutyl ketone, toluene, n-hexane, N, N-dimethylformamide, Acetone and ethanol may be used as the solvent.

According to one embodiment, the substrate may be selected from the group consisting of quartz, glass, silicon, sapphire, and a metal film.

According to one embodiment, the step of pressing and transferring the coated SOG layer onto a substrate may be performed by pressurizing the substrate at room temperature to 50 ° C for 1 to 10 minutes under a pressure of 1 to 10 atm.

According to one embodiment, the step of coating the SOG nanopattern transferred on the substrate with a self-assembled monolayer (SAM) may be further included.

According to one embodiment, the step of depositing the transparent electrode material on the SOG nanopattern transferred to the substrate may be further included.

According to one embodiment, the transparent electrode material may be selected from the group consisting of ITO, IZO, ZnO, AZO, and SnO ₂ : F.

According to one embodiment, the SOG nanopattern may further include ultraviolet / ozone (UV / ozone) treatment or oxygen plasma treatment.

According to another aspect of the present invention, there is provided a mold for a nanoimprint comprising the substrate on which the nano pattern is formed.

According to another aspect of the present invention, an optical element including the substrate on which the nanopattern is formed may be provided.

According to the present invention, since only the master mold is prepared, the SOG nanostructure having the same shape as the master mold can be transferred to the substrate by a simple pressing process without requiring an adhesive layer, ultraviolet rays, heat treatment, etc., A nano pattern can be formed on a substrate at low cost. In addition, SiO ₂ nanostructures can be fabricated through a simple annealing process, and SOG nanostructures can be easily transferred onto a curved substrate because PDMS (polydimethyl siloxane), h-PDMS, or PVA (polyvinyl acetate) resin molds are flexible, And can be easily applied to high-efficiency optoelectronic devices.

Hereinafter, the present invention will be described in detail.

The present invention provides a method for directly transferring a nano pattern on a substrate using SOG so that the nano pattern can be easily implemented on a substrate. This includes preparing a mold having a nanopattern in PDMS (polydimethyl siloxane), h-PDMS, or PVA (polyvinyl acetate) resin; Coating a spin-on glass (SOG) layer on the mold; And depositing a PDMS or PVA resin mold on which the SOG layer is formed such that the upper surface of the substrate and the SOG forming surface meet, and transferring the SOG layer onto a substrate; And removing the PDMS or PVA resin mold.

The reason why PDMS (Polydimethyl siloxane), h-PDMS or PVA (polyvinyl acetate) resin is used is that when these resins are coated with SOG, they can be easily transferred to a substrate, Because it has high chemical resistance and does not cause damage by the SOG solution, and it is also advantageous in that it can be transferred to a substrate having a curved surface.

In this case, the SOG is a silicate, a siloxane, a methyl silsequioxane (MSQ), a hydrogen silsequioxane (HSQ), a perhydropolysilazane (SiH ₂ NH) n)), polysilazane, and mixtures thereof.

SOG is light-permeable and can be any material that does not lose its optical properties when coated on a substrate, and can be selected from the group consisting of methyl isobutyl ketone, toluene, n-hexane, N, N-dimethyl The organic solvent is present in a liquid state in an organic solvent such as N, N-dimethylformamide, acetone and ethanol, coated by a method such as spin coating, and then transferred to a desired substrate Anything is possible.

The SOG layer may be coated by any method that can form a SOG layer on the mold of the resin, such as spin coating, vapor deposition, or bar coating.

In the step of coating the SOG layer, it is preferable that the liquid SOG containing 5 to 25% by weight of the SOG is applied by spin coating at 500 to 7000 rpm for 10 to 30 seconds to form a film with a thickness of 50 to 1000 nm. If the concentration of SOG is too low and the concentration of SOG is lower than 5% by weight, the formation of the SOG layer becomes difficult. If the concentration exceeds 25%, the viscosity of the liquid SOG increases and the film may be formed to a desired thickness, have. When the thickness of the SOG layer is thinner than 50 nm, it is likely to be damaged during the transfer process. When the thickness of the SOG layer is thicker than 1000 nm, the optical or other characteristics of the SOG nano pattern can not be sufficiently exhibited. It is difficult to obtain, and the problem of economical efficiency in transferring unnecessarily thick layer to the substrate beyond desired is followed, which is not preferable.

The substrate may be selected from the group consisting of quartz, glass, silicon, sapphire, and a metal thin film, but any substrate having a surface property capable of being transferred under the conditions according to the present invention is possible.

The step of pressurizing and transferring the coated SOG layer to the substrate may be performed by pressurizing the substrate at a temperature of 1 to 10 atm and a temperature of from room temperature to 50 ° C for 1 to 10 minutes. When the pressure is lower than 1 atm, Bubbles may form between the pressing surfaces or no pressing may occur at all. If a pressure higher than 10 atm is applied, it may affect the nanopattern generated in the SOG, and PDMS, h-PDMS or PVA resin mold and SOG So that the separation of the particles does not easily occur.

 In the temperature condition at the time of transfer, most of the organic solvent is removed after the spin coating process, so that the flowability of the SOG thin film is almost lost. Therefore, the temperature at the time of transferring may be sufficient at room temperature, The residual organic solvent may disappear and the transfer may not occur smoothly, which is also undesirable.

The pressing time at the time of transferring is preferably from 1 to 10 minutes, and if the holding time is shorter or longer than this, the transfer does not occur smoothly, and the separation of the thin film may be less likely.

1 shows a schematic diagram of a direct SOG nanopattern formation technique. First, a PDMS (Polydimethyl Siloxane) resin mold with nanopatterns is prepared and the SOG solution is spin-coated on the PDMS resin mold. During this spin coating process, most of the organic solvent in the SOG solution is removed and a portion of the organic solvent is absorbed in the PDMS mold. Then, when the PDMS mold coated with the SOG film is placed on the substrate and the pressing process is performed at a pressure of 1 to 10 atm, a part of the organic solvent absorbed in the PDMS mold is released to the interface between the SOG and the PDMS mold, Separation of the SOG and PDMS molds is facilitated and the SOG nanostructure is transferred to the substrate.

The SOG / quartz hybrid mold can be easily fabricated using the technique developed in the present invention. Existing molds for ultraviolet nanoimprint (UV NIL) are used to etch quartz wafers or to replicate polymer-based molds. However, the technique of patterning and etching the quartz wafer is very difficult and costly to manufacture. The polymer mold can be easily copied from the existing master mold, but the mechanical strength is relatively low. The SOG / quartz hybrid mold as shown in FIG. 2, which may be provided in the present invention, is transparent in the ultraviolet region, has a very high mechanical strength, and can easily produce a silane-based superhydrophobic self- assembled monolayer (SAM) It can be said that it is very suitable as a mold for ultraviolet nanoimprint.

A self-assembled monolayer (SAM) is an organic monolayer formed spontaneously on a solid surface. The molecule that forms this self-assembled monolayer (SAM) consists of three parts. First, it is divided into the reactor of the head part which binds to the substrate, the long alkane chain of the body part which enables regular molecular film formation, and the functional part of the tail part which controls the function of the molecular membrane. These self-assembled monolayers (SAMs) form a direct bond between the surface of the substrate and the molecules forming the membrane, which makes it very robust, and is not affected by the shape or size of the substrate. And it is easy to maximize.

The material forming the self-assembled monolayer (SAM) is a self-assembled monolayer material made of an alkanoic acid that forms an ionic bond with a substrate, an organosulfur that forms a charge-transfer complex Self-assembled monolayer materials made of self-assembled monolayer materials, or self-assembled monolayer materials made of organosilicon that make pure covalent bonds.

SAMs can be divided as follows depending on the interaction with the substrate. SAMs made from alkanoic acids that make ionic bonds with the substrate, SAMs made from organosulfur that form charge-transfer complexes, and SAMs made from organosilicon with pure covalent bonds.

The step of forming the self-assembled monolayer generally comprises: dissolving the self-assembled monolayer in a solvent to prepare a self-assembled monolayer solution; And immersing the substrate on which the oxide film is formed in the self-assembled monolayer solution.

In the present invention, a method of forming a self-assembled monolayer on a nano-patterned SOG is as follows.

A solution of heptadecafluoro-1,1,2,2-tetra-hydrodecyl trichlorosilane (CF3 (CF2) 5 (CH2) 2SiCl3), HDFS (trichlorosilane) Dispersed in a volume ratio. An alkyl group containing a silane group or an alkyl group substituted with a fluorine is prepared in a general organic solvent at a low concentration of 10 ^-3 mol or less and a SOG / quartz hybrid mold is added for 10 minutes The HDFS-SAM film is formed naturally on the SOG surface, so that it is possible to easily coat the release film that can solve the adsorption problem that may occur during the nanoimprint lithography process.

According to an embodiment of the present invention, a step of coating the SOG nano pattern transferred on the substrate with a self-assembled monolayer (SAM) may be used, and the nanoimprint may be used as a mold for nanoimprint.

According to an embodiment of the present invention, a step of depositing a transparent electrode material on the SOG nanopattern transferred to the substrate may be further included. The transparent electrode material may be selected from the group consisting of ITO, IZO, ZnO, AZO, and SnO ₂ : F. The SOG nanopattern may be treated by ultraviolet / ozone treatment or oxygen plasma treatment .

Recently, a moth eye anti-reflection layer having a periodically aligned cone array pattern having a diameter of 200 to 300 nm has been developed. This suppresses the total reflection by causing the light to gradually change the refractive index by the periodic nanostructure. In order for the moth eye effect to be realized properly, the nanostructures must be made at a high density and at the same time have a slightly inclined structure rather than a vertical shape. In order to manufacture moth-eye nanostructures using existing nanopatterning technology, a very complicated process is required and the process cost is also very high. Therefore, a more economical technique is required to apply the moth-eye pattern antireflection film to the actual industry. The direct transfer technology using SOG according to the present invention is expected to be easy to apply the mothball antireflection film pattern to various optical elements because the pattern that is not a vertical shape can be transferred directly to the SOG film and the process is simple.

The direct SOG moth eye pattern transfer technology according to the present invention can be applied to various optoelectronic devices. FIG. 3 shows an application example of improving the efficiency of an OLED element by transferring an SOG or an obtuse pattern to a protective capping glass surface of an OLED element or by transferring an SOG moth eye pattern onto a glass surface used as a substrate. By using the structure as shown in the figure, it is possible to realize an OLED device having higher efficiency than the conventional glass.

FIG. 4 is a cross-sectional view illustrating a method of fabricating a SOG moth eye pattern on an ordinary glass surface and depositing a transparent electrode material (TCO) such as ITO, IZO, ZnO, AZO and SnO ₂ : And the reflection generated at the interface of the electrode material material is reduced to improve the efficiency of the optoelectronic device using the transparent electrode material. In this case, in order to improve the conductivity of the transparent electrode material, annealing is required. During the annealing, the SOG moth eye pattern may be removed by shrinkage. This problem can be solved by annealing the SOG surface by ultraviolet / ozone (UV / ozone) treatment or oxygen plasma treatment of the SOG moth eye pattern without annealing the pattern.

As shown in FIG. 4, when the transparent electrode glass substrate having the SOG or SiO ₂ moth eye patterns inserted therein is applied to a photoelectric device such as a thin film solar cell or an OLED device, its efficiency can be remarkably improved.

Hereinafter, the present invention will be described in more detail with reference to Examples. It should be understood, however, that these examples are for illustrative purposes only and are not to be construed as limiting the scope of the present invention.

Example  One. SOG - PDMS Suzy Mold  Direct formation of nanopattern using

A 2x2 cm ² PDMS resin mold was prepared by using a master mold having a moth-eye nano pattern formed thereon by a nanoimprinting technique, and a 22 wt% hydrogensilcequioxane (HSQ) solution was spun on a PDMS mold at 3000 rpm for 30 seconds Respectively. Then, a PDMS mold coated with a hydrogensilquioxane (HSQ) film was placed on a borosilicate glass substrate and pressed at a pressure of 5 atm for 10 minutes. As a result, a borosilicate glass substrate having a light transmittance remarkably improved as compared with a region not coated with a hydrogensilquioxane (HSQ) film was obtained.

Example  2. SOG /quartz hybrid Mold Manufacturing example

A 2x2 cm ² PDMS resin mold was prepared by using a master mold having a moth-eye nano pattern formed thereon using a nanoimprinting technique. The mold was then extruded into a PDMS resin mold at 3000 rpm using a 10 to 22 wt% hydrogensilquioxane (HSQ) Spin coating was carried out for 30 seconds. Subsequently, a PDMS resin mold coated with a hydrogensilquioxane (HSQ) film was placed on a quartz wafer substrate, and the PDMS resin mold was separated by pressurizing the substrate with a pressure of 5 atm for 10 minutes. As a result, a nanoscale hydrogel silsesquioxane (HSQ) thin film was transferred onto a quartz wafer, and then a transparent nanomold for UV nanoimprint lithography can be manufactured by coating HDFS-SAM by the above-described method.

Example  3. SOG  Formed nanopattern OLED  Element Manufacturing example

A nano-patterned PDMS resin mold was prepared by using a master mold having a nano-sized nano pattern formed thereon using a nanoimprinting technique. A 10 wt% hydrogensilsquioxane (HSQ) solution was spun on the PDMS mold at 3000 rpm for 30 seconds After the coating, a PDMS mold having hydrogel silsesquioxane (HSQ) film formed thereon was placed on the backside of the substrate of the OLED device or capping glass, and the PDMS resin mold was separated from the PDMS resin mold by pressing at 5 atm for 10 minutes. (HSQ) moth nanopattern was transferred to the substrate. An OLED device in which light generated through such a technique is transmitted through the backside of the substrate or the capping glass can be manufactured.

Example  4. SOG Moth eye  In an optoelectronic device in which a transparent electrode material is deposited on a pattern Manufacturing example

A PDMS resin mold having a size of ² x ² cm ^{2 was} prepared by using a master mold in which a moth-eye nano pattern was formed using a nanoimprinting technique, and a 22 wt% hydrogensilcequioxane (HSQ) solution was spun on a PDMS mold at 3000 rpm for 30 seconds Respectively. Subsequently, a PDMS mold coated with a hydrogensilquioxane (HSQ) film was placed on a heat-resistant glass substrate such as a borosilicate glass substrate and pressed at a pressure of 5 atm for 10 minutes. The PDMS mold was then removed from the substrate and the hydrogensilcequioxane (HSQ) moth nanopattern was transferred to the substrate. The transferred nanopattern was oxidized by ultraviolet / ozone treatment or oxygen plasma process and annealed at 400 ° C to have sufficient heat resistance. Through this process, the hydrogensilcequioxane (HSQ) material was converted to SiO ₂ material, resulting in SiO ₂ mica nanopatterns. After the transparent electrode material such as ITO was deposited on the SiO ₂ mica nanopattern, annealing was performed at a temperature of 400 ° C., which is generally carried out to improve the conductivity of ITO. When the thin film solar cell or the OLED device is fabricated on the ITO thin film, the efficiency of the optoelectronic device is improved by the SiO ₂ mica nano pattern between the substrate and the ITO thin film.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Fig. 1 shows a schematic diagram of a technique for forming an SOG nanostructure.

2 is a schematic diagram showing the structure of a SOG / quartz hybrid mold.

FIG. 3 shows an application example of improving the efficiency of an OLED element by transferring a SOG moth eye pattern onto a protective capping glass surface of an OLED element or by transferring an SOG moth eye pattern onto a glass surface used as a substrate.

FIG. 4 is a cross-sectional view of a TCO material having a relatively high refractive index by forming an SOG moth eye pattern on an ordinary glass surface and depositing a transparent electrode material (TCO, ex> ITO, IZO, AZO, SnO ₂ : F) And the efficiency of the optoelectronic device using the transparent electrode material is improved.

Claims (12)

Preparing a resin mold having nanopatterns formed on at least one resin selected from the group consisting of PDMS (polydimethyl siloxane), h-PDMS, and PVA (polyvinyl acetate); Coating a spin-on glass (SOG) layer on the resin mold; And Stacking the resin mold having the SOG layer formed thereon so that the upper surface of the substrate and the SOG forming surface meet, and pressing the SOG layer to a substrate by pressurizing the substrate at a temperature of from room temperature to 50 ° C for 1 to 10 minutes under a pressure of 1 to 10 atm; And Removing the resin mold; And forming a nano pattern on the substrate using the SOG. The method of claim 1, wherein the step of coating a spin-on glass (SOG) layer on the mold comprises 5-25% by weight of SOG, and isobutyl ketone (Methyl isobutyl ketone) Liquid SOG having a solvent selected from the group consisting of n-hexane, N, N-dimethylformamide, acetone and ethanol is heated at 500 to 7000 rpm By spin coating for 10 to 30 seconds, and forming a film with a thickness of 50 to 1000 nm. The method for forming a nanopattern on a substrate using SOG. The method of claim 2, wherein the liquid SOG is selected from the group consisting of silicate, siloxane, methyl silsequioxane (MSQ), hydrogen silsequioxane (HSQ), perhydro polysilane Wherein the SOG is selected from the group consisting of perhydropolysilazane ((SiH ₂ NH) n)), polysilazane, and mixtures thereof. delete The method of claim 1, wherein the substrate is selected from the group consisting of quartz, glass, silicon, sapphire, and a metal thin film. delete The method of claim 1, further comprising: after removing the resin mold, coating a self-assembled monolayer (SAM) on the SOG nano pattern formed on the substrate. The method of claim 1, further comprising: after removing the resin mold, depositing a transparent electrode material on a SOG nano pattern formed on a substrate. The method of claim 8, wherein the transparent electrode material ITO, IZO, ZnO, AZO, and SnO _2: A method of forming a nano pattern on a substrate using a SOG, characterized in that selected from the group consisting of F. 9. The method of claim 8, further comprising UV / ozone treatment or oxygen plasma treatment of the SOG nanopattern. A mold for a nanoimprint comprising a substrate on which a nano pattern is formed by the method according to any one of claims 1 to 3, 5 and 7. An optical element comprising a substrate on which a nanopattern is formed by the method according to any one of claims 1 to 3, 5 and 8 to 10.

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