KR20160025061A - Method of manufacturing a photo-functional pattern structure - Google Patents

Abstract

According to a method to manufacture a photo-functional pattern structure, a photo-functional pattern, formed of a first material with a first refractive index and including an even part in the upper part, is formed on a substrate, and a flattening layer, formed of a second material with a second refractive index, different from the first refractive index, and including a flattened upper surface, is formed on the photo-functional pattern. The purpose of the present invention is to provide a method to manufacture a photo-functional pattern structure with improved surface roughness.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for manufacturing a photostructured pattern structure,

The present invention relates to a method of manufacturing a photo-functional pattern structure, and more particularly, to a method of manufacturing a photo-functional pattern structure having a concavo-convex shape.

Solar cells and light emitting diodes correspond to optoelectronic devices that absorb light or generate light. The solar cell absorbs light to generate electricity, while the light emitting diode generates light while electrons in the excited state move to a stable state.

The solar cell can be classified into a solar cell that generates electricity by rotating the turbine using steam generated by the solar heat, and a solar cell that converts sunlight (photons) into electrical energy using the property of the semiconductor .

[0003] Silicon-based solar cells, which are a kind of the above-described photovoltaic cells and have excellent price-generating power up to now, are dominating the market and research. However, the above-described silicon-based solar cell has a complicated manufacturing process and has a limitation in cost reduction due to a high process cost, and also a usable substrate is limited. The thin film solar cell developed as an alternative to this can be applied to various fields because it can be manufactured on various substrates such as glass, metal, and polymer. In addition, the manufacturing process is simple and the manufacturing process cost can be reduced. However, the thin film solar cell has a disadvantage that it does not absorb light enough to make the light absorbing layer very thin, and accordingly, the efficiency is low.

In order to solve these drawbacks, many studies including material research, optimization of manufacturing process, and optical functional pattern have been carried out. Among them, the photofunctional pattern is a big research field showing how important the light management of the solar cell is, and it has greatly contributed to the power generation efficiency of the solar cell. However, when a photo-functional pattern is applied to the interior of an optoelectronic device, it may easily cause degradation of device characteristics due to surface roughness due to the photo-functional pattern. Therefore, it is essential to realize a pattern layer having low roughness and optical function in order to improve the efficiency of the thin film type solar cell.

Meanwhile, due to interest in flexible devices and increase in demand, researches on fabrication of optoelectronic devices including flexible substrates are underway, and studies on organic devices suitable for the flexible substrates have also been rapidly increasing.

The organic device is advantageous in that it can be easily manufactured, can be made large, and can be fabricated on a flexible substrate, so that it can be applied to various fields. However, it has a disadvantage that the luminous efficiency of the organic device having such various advantages is low.

In particular, the performance of a light emitting diode is largely divided into internal quantum efficiency and external quantum efficiency. Internal quantum efficiency refers to the amount of photons generated according to injected electrons, and external quantum efficiency refers to the degree to which generated photons are extracted to the outside of the device . The external quantum efficiency is determined according to the light extraction efficiency.

Recently, the organic quantum efficiency of the organic light emitting diode has been greatly improved due to the research and development of many materials, and the efficiency of the organic light emitting diode is almost 100%. However, the light extraction efficiency, which is one of the main parameters for determining the luminous efficiency of the organic light emitting diode, Which is a major cause of lowering the final luminous efficiency of the organic light emitting device. As a solution for this, a photo-functional pattern can be mentioned. The photo-functional pattern can be formed into a structure having a size of several hundred nanometers to several microns according to the wavelength range or intensity of light transmittance and light scattering.

However, when inserting the above-mentioned optical functional pattern into the device, there is a problem in that it causes a structural effect on the inside of the device and induces a leakage current, thereby deteriorating the device characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method of manufacturing a photofunctional pattern structure having an improved surface roughness.

According to another aspect of the present invention, there is provided a method for manufacturing a photo-functional pattern structure, the method comprising: forming a photo-functional pattern on a substrate, the photo-function pattern having a concavo- A planarizing layer having a top surface made of a second material having a second refractive index different from the first refractive index and being planarized is formed.

In an embodiment of the present invention, the difference between the first refractive index and the second refractive index may be 0.2 or more.

In one embodiment of the present invention, one of the photo-functional pattern and the planarization layer includes an SOG material, and the other may include a polymer organic material having nanoparticles dispersed therein. Here, the nanoparticle may include titanium oxide or zirconium oxide. In addition, the remaining one containing the nanoparticle-dispersed polymer organic material may be annealed to increase the hardness of the remaining one.

In one embodiment of the present invention, the photo-functional pattern may be formed by a hot embossing process using a stamp having a shape corresponding to the irregularities with respect to a material having the liquid phase and made of the first material.

In one embodiment of the present invention, the photofunctional pattern may be formed by an imprint process and a transfer process using a mold having the shape corresponding to the irregularities with respect to a material having a liquid phase and made of the first material.

In the above-described case, by forming the optical functional pattern with the planarizing layer, an improved roughness can be realized while maintaining the optical function due to the refractive index difference between the planarizing layer and the optical functional pattern. Accordingly, when a photo-functional pattern structure having reduced roughness is applied to the device, it can be applied to the inside without deteriorating the characteristics of the optoelectronic device such as the solar cell or the organic light emitting device. Furthermore, the efficiency of the optoelectronic device can be improved by the optical function of the photo-functional pattern.

FIG. 1 is a cross-sectional view illustrating a method for fabricating a photo-functional pattern structure according to an embodiment of the present invention. Referring to FIG.
2 is a cross-sectional view illustrating a method of fabricating a photo-functional pattern structure according to an embodiment of the present invention.
3 is a graph for explaining a change in the refractive index of the SOG material depending on the amount of titanium oxide dispersed.
4 is a graph for explaining the hardness of the SOG material before and after the annealing process according to the amount of dispersion of titanium oxide.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the accompanying drawings, the sizes and the quantities of objects are shown enlarged or reduced in size in order to clarify the present invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprise", "comprising", and the like are intended to specify that there is a feature, step, function, element, or combination of features disclosed in the specification, Quot; or " an " or < / RTI > combinations thereof.

On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Fabrication method of photo-functional pattern structure

FIG. 1 is a cross-sectional view illustrating a method for fabricating a photo-functional pattern structure according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 1, in a method of manufacturing a photo-functional pattern structure according to an embodiment of the present invention, a high-refraction material layer is formed on a film. The high refractive index material layer may be made of a high refractive index material. For example, the high refractive index material layer may be formed of a polymer organic material having nanoparticles dispersed therein. The nanoparticles may include titanium oxide, copper oxide, tin oxide, silicon oxide, or zirconium oxide. At this time, the high refractive index material layer can maintain a viscosity higher than a certain level. The refractive index of the high refractive index material layer can be controlled according to the dispersion amount of the nanoparticles. For example, the refractive index of the high refractive index material layer may have an increased refractive index as the dispersion amount of the nanopattern increases.

Thereafter, the high-refractive-index material layer is pressed with a stamp having a concavo-convex shape to form a photo-functional pattern having irregularities on the concavo-convex shape. At this time, the high refractive material layer is cured by heating the high refractive material layer. Therefore, the photo-functional pattern having irregularities on the film can be formed on the film.

The irregularities may have various shapes such as a circular columnar shape, a polygonal columnar shape, a stripe shape, and the like.

Thereafter, the stamp is removed from the photofunctional pattern, and a low refractive material layer made of a low refractive material is formed on the photofunctional pattern. The low refractive index material layer may be made of a polymer material. The low refractive index material layer may be formed of a spin on glass (SOG) material. The SOG material may include, for example, silicate, siloxane, methylsilsequioxane (MSQ) Hydrogen silsequioxane (HSQ), perhydropolysilazane ((SiH2NH) n), polysilazane, or mixtures thereof.

The low refractive index material layer may be formed, for example, by a spin coating process. According to the spin coating process, the liquid SOG material can be processed at a rotation speed of 500 to 7,000 rpm for 10 to 30 seconds. Also, the viscosity of the SOG material can be suitably adjusted.

Subsequently, a flattening layer is formed on the photofunctional pattern by pressing the low refractive index material layer with a press having a flat bottom surface. At this time, the low refractive index material layer can be cured by applying heat or ultraviolet rays to the low refractive index material layer.

Thus, a photo-functional pattern structure in which a photo-functional pattern and a planarization layer are sequentially laminated on a film can be produced.

On the other hand, the order of the high refractive index material layer and the low refractive index material layer may be reversed.

In one embodiment of the present invention, an annealing process may be further performed on the photo-functional pattern including the polymer organic material in which the nanoparticles are dispersed. The hardness of the photo-functional pattern may be increased through the annealing process.

2 is a cross-sectional view illustrating a method of fabricating a photo-functional pattern structure according to an embodiment of the present invention.

Referring to FIG. 2, a layer of high-refraction material is formed on the mold. The high refractive index material layer may be made of a high refractive index material. For example, the high refractive index material layer may be formed of a polymer organic material having nanoparticles dispersed therein. The nanoparticles may include titanium oxide, copper oxide, tin oxide, silicon oxide, or zirconium oxide. At this time, the high refractive index material layer can maintain a viscosity higher than a certain level. The mold may also be made of a PDMS material. The upper surface of the mold is also provided with concavities and convexities. The unevenness has a shape corresponding to the unevenness of the subsequently formed photo-functional pattern.

On the other hand, the high refractive index material layer can be formed through a spin coating process.

Then, the photoflective pattern is formed on the substrate by transferring the layer of high refractive index material to the substrate. That is, after arranging the high refractive index material layer and the substrate so as to face each other, the mold is removed to form a photo-functional pattern on the substrate on which irregularities are formed. The substrate may be a glass substrate.

Thereafter, a low refractive index material layer is formed on the photo-functional pattern. The low refractive index material layer may be formed through a spin coating process. The low refractive index material layer may be made of a polymer material. The low refractive index material layer may be formed of a spin on glass (SOG) material. The SOG material may include, for example, silicate, siloxane, methylsilsequioxane (MSQ) Hydrogen silsequioxane (HSQ), perhydropolysilazane ((SiH2NH) n), polysilazane, or mixtures thereof.

Thereafter, a flattening layer is formed on the photo-functional pattern by pressing with a stamp having a flattened lower surface with respect to the low refractive index material layer. At this time, the planarization layer may be formed by heating the low refractive index material or irradiating ultraviolet rays.

Thus, a photo-functional pattern structure in which a photo-functional pattern and a planarization layer are sequentially laminated on a glass substrate can be manufactured.

On the other hand, the order of the high refractive index material layer and the low refractive index material layer may be reversed.

In one embodiment of the present invention, an annealing process may be further performed on the photo-functional pattern including the polymer organic material in which the nanoparticles are dispersed. The hardness of the photo-functional pattern may be increased through the annealing process.

3 is a graph for explaining a change in the refractive index of the SOG material depending on the amount of titanium oxide dispersed.

Referring to FIG. 3, the refractive index of a high refractive index material in which nanoparticles of titanium oxide are dispersed in an SOG material is measured. As shown in the figure, the refractive index of the high refractive index material increases as the amount of nanoparticle dispersion increases.

4 is a graph for explaining the hardness of the SOG material before and after the annealing process according to the amount of dispersion of titanium oxide.

Referring to FIG. 4, the hardness of a high refractive index material in which nanoparticles of titanium oxide are dispersed in the SOG material was measured. As shown in the figure, when the annealing process for the high refractive index material is performed, the hardness is increased.

When the photofunctional structure is applied to an organic light emitting device, the photo-functional pattern may correspond to an electron transport layer or a hole transport layer. As a result, the photo-functional pattern structure including the photo-functional pattern and the planarization layer having different refractive indexes has excellent surface flatness (low surface roughness) and at the same time has a different refractive index, The optical characteristics and the electrical characteristics of the device can be improved.

The method for fabricating a photo-functional structure according to embodiments of the present invention can be applied to an organic light emitting device and a thin film solar cell.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (7)

Forming a photo-functional pattern of a first material having a first refractive index on a substrate and having irregularities on the first material; And
And forming a planarization layer on the photofunctional pattern, the planarization layer comprising a second material having a second refractive index different from the first refractive index and having a planarized top surface. The method as claimed in claim 1, wherein the difference between the first refractive index and the second refractive index is 0.2 or more. The method of claim 1, wherein one of the photo-functional pattern and the planarization layer comprises a SOG material, and the other comprises a polymer organic material having nanoparticles dispersed therein. 4. The method of claim 3, wherein the nanoparticle comprises titanium oxide or zirconium oxide. The method as claimed in claim 3, further comprising annealing the remaining one of the nanoparticle-dispersed polymer organic materials to increase the hardness of the remaining one of the nanoparticles. Gt; The method as claimed in claim 1, wherein the step of forming the photo-functional pattern comprises a hot embossing process using a stamp having a shape corresponding to the unevenness of the material having the liquid phase, Method of manufacturing a pattern structure. The method of claim 1, wherein the forming of the photo-functional pattern comprises an imprint process and a transfer process using a mold having the shape corresponding to the irregularities with respect to a material having a liquid phase, A method for manufacturing a photofunctional pattern structure.

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