KR20100121943A - Method of fabricatinf photonic crystal type color filter - Google Patents

Abstract

PURPOSE: A method of manufacturing a photonic crystal type color filter is provided to improve the regularity of a pattern by reducing the number of process. CONSTITUTION: A refraction material layer is formed on a substrate(130) and is pushed through a mold to form a two-dimensional photonic crystal color pattern structure. Crystallizing energy is applied to the refraction material layer. The mold adopts the two- dimensional photonic crystal color pattern structure and then the mold is separated.

Description

Method of manufacturing photonic crystal color filter {Method of fabricatinf photonic crystal type color filter}

The disclosed embodiments relate to a method of manufacturing a photonic crystal color filter.

As a method of manufacturing a color filter, a pigment dispersion method is mainly used in which a solution obtained by dispersing a pigment in a photoresist is applied onto a substrate and patterned to form pixels of each color. Since the pigment dispersion method uses a photolithography process, it is possible to realize a large area, to be thermally and chemically stable, and to secure color uniformity. However, such pigment type color filters produce high color purity color filters because their color characteristics are determined by the inherent absorption spectrum of the pigment and the light transmittance decreases as the thickness of the color filter becomes thicker. There is a problem that the brightness is lowered.

Recently, photonic crystal type color filters based on structural colors have been studied. Photonic crystal color filters use nanostructures smaller than the wavelength of light to control the reflection or absorption of light incident from the outside, thereby reflecting (or transmitting) light of a desired color and transmitting (or reflecting) light of other colors. Let's do it. The photonic crystal color filter has a structure in which nano-sized unit blocks are periodically arranged at regular intervals. The photonic crystal color filter has an advantage of excellent wavelength selectivity and easy color bandwidth adjustment by fabricating a structure suitable for a specific wavelength because its optical properties are determined by the size and period of the nanostructure. And, due to such characteristics, the photonic crystal color filter may be more usefully applied to a reflective liquid crystal display device using external light having a very wide spectrum distribution.

Embodiments of the present invention provide a method of manufacturing a photonic crystal color fill that can reduce the number of processes and improve the uniformity of the pattern.

A method of manufacturing a color filter according to an embodiment of the present invention includes forming a refractive material layer on a substrate; Supplying crystallization energy to the refractive material layer while pressing the refractive material layer by using a mold having a two-dimensional photonic crystal color pattern structure to form the refractive material layer into the two-dimensional photonic crystal color pattern structure; And spacing the mold.

The crystallization energy may be provided by scanning an excimer laser at least once on the refractive material layer.

The refractive material layer is an amorphous silicon layer and is converted into a polysilicon layer by the crystallization energy. After forming the refractive material layer on the substrate, a dehydrogenation process for removing hydrogen in the amorphous silicon layer may be performed.

The manufacturing method may further include forming a barrier layer between the substrate and the refractive material layer.

A method of manufacturing a color filter according to an embodiment of the present invention includes forming a refractive material layer on a substrate; Pressing the refractive material layer using a mold having a two-dimensional photonic crystal color pattern structure to mold the refractive material layer into the two-dimensional photonic crystal color pattern structure; Spacing the mold; And recrystallizing the refractive material layer by supplying crystallization energy to the refractive material layer.

The crystallization energy may be provided by scanning an excimer laser at least once on the refractive material layer.

The manufacturing method may further include removing impurities remaining in the refractive material layer formed into the two-dimensional photonic crystal color pattern structure by an oxygen ashing process before performing the recrystallization step. The manufacturing method may further include forming a support layer for preventing deformation of the two-dimensional photonic crystal color pattern structure formed on the refractive material layer in the recrystallization process after removing the impurities. . The forming of the support layer may include depositing at least one of SiO 4, Si 3 N 4, ITO, and Ni along the two-dimensional photonic crystal color pattern structure formed on the refractive material layer. The forming of the support layer may further include filling the support material with the concave portion of the two-dimensional photonic crystal color pattern structure formed on the refractive material layer.

The refractive material layer may be a silicon-based nanoparticle solution, the molding process may include a process of UV treatment or heat treatment to the refractive material layer, the refractive material layer is a polysilicon layer by the crystallization energy Is converted to.

The refractive material layer may be a polysilane resin, and the molding process may include a UV treatment or a heat treatment process for molding the polysilane resin, and the refractive material layer is converted into a polysilicon layer by the crystallization energy. do.

The manufacturing method may further include forming a barrier layer between the substrate and the refractive material layer.

According to the method of manufacturing a color filter according to the present invention, a process technology level is relatively lower than that of a monocrystalline silicon-based manufacturing method by recrystallizing amorphous silicon, a silicon-based nanoparticle solution, or a polysilane resin and converting it into polysilicon. Also, the photonic crystal layer made of polysilicon can be easily formed.

According to one embodiment of the method of manufacturing a color filter according to the present invention, an etching process is excluded in the process of forming the photonic crystal structure, and the precision of the photonic crystal pattern depends on the precision of the mold which can be manufactured with high precision. Thus, production of color filters of good quality is possible. In addition, since the etching process is excluded and the molding and recrystallization are performed at the same time, the manufacturing process can be greatly simplified, thereby reducing the process cost and time.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of description.

1 is a perspective view showing an example of a color filter manufactured by an embodiment of the manufacturing method according to the present invention, Figure 2 is a cross-sectional view of FIG. Referring to the drawings, the color filter 100 includes a substrate 130 and a photonic crystal layer 160. The substrate 130 may be transparent. The barrier layer 150 may be provided between the substrate 130 and the photonic crystal layer 160.

The photonic crystal layer 160 has a two-dimensional photonic crystal color pattern structure that reflects light having a wavelength band corresponding to the photonic bandgap by periodic refractive index distribution. The photonic crystal layer 160 has a structure in which the first material 162 and the second material 166 are periodically arranged. The first material 162 has a relatively high refractive index relative to the second material 166. The first material 162 forms an island-shaped two-dimensional photonic crystal color pattern. Although shown in the shape of a rectangular parallelepiped, a circle or polygonal pillar shape is possible and may have various other shapes. The first material 162 has a larger refractive index than the second material 166. For example, the difference between the real part component of the refractive index of the first material 162 and the refractive index of the second material 166 is two or more. Can be. In addition, the imaginary component of the refractive index of the first material 162 and the refractive index of the second material 166 may be 0.1 or less in the visible light wavelength band. It is intended to use materials with small minor component values. The first material 162 may be, for example, single crystal silicon or polysilicon. The concave portion of the two-dimensional photonic crystal color pattern structure formed by the first material 162 may be filled by the second material 162. The second material 166 may be, for example, air. In this case, the process of forming the second material 166 in FIG. 1 may be omitted. The second material 166 may serve to support the two-dimensional photonic crystal color pattern structure formed by the first material 162. In this case, for example, PC, PS, PMMA, Si ₃ N ₄ , SiO _2, or the like may be employed as the second material 166. Such a structure serves to, for example, form a two-dimensional photonic crystal color pattern structure using the first material 162 as amorphous silicon, and then protect the pattern shape without damaging the crystal shape in single crystal silicon or polysilicon. Can be selected to

The substrate 130 is provided to serve as a waveguide. Only the light having a specific wavelength is reflected by the crystal structure of the photonic crystal layer 160, and the remaining light is transmitted and trapped in the substrate 130. A glass substrate may be used as the substrate 130.

The barrier layer 150 is provided between the substrate 130 and the photonic crystal layer 160. The barrier layer 150 may include, for example, impurities in the glass substrate used as the substrate 130 during the crystallization process, and may be incorporated into the silicon material used as the first material 162 of the photonic crystal layer 160 to crystallize the silicon. It is to prevent lowering. The barrier layer 150 may be formed of a material having a refractive index similar to that of the substrate 130. As the material of the barrier layer 150, a material such as a material selected as the second material 166 may be used.

In the case of the reflective color filter, an absorbing layer (not shown) may be further provided below the substrate 130. The absorbing layer may improve reflectance characteristics of the color filter 100 by absorbing light trapped in the substrate 130.

As shown in FIG. 2, the photonic crystal layer 160 may include, for example, three regions 160R, 160G, and 160B that respectively filter R, G, and B light. To this end, the shape and period of the first material 162 forming the three regions 160R, 160G, and 160B are determined differently to have photonic bandgaps corresponding to red, green, and blue, respectively. In the case of the reflective color filter, the three regions 160R, 160G, and 160B reflect red (R), green (G), and blue (B) light from the incident light (L), respectively. In the case of the transmissive color filter, the three regions 160R, 160G, and 160B transmit red (R), green (G), and blue (B) light, respectively. Although only three regions 160R, 160G, and 160B are illustrated in FIG. 2, the color filter 100 has a structure in which three regions 160R, 160G, and 160B are repeatedly arranged as illustrated in FIG. 3.

The optical filter 100 having the structure described above reflects light of a specific wavelength band by a photonic cystal color pattern structure that forms a periodic refractive index distribution. At this time, since the band band and width of the reflected light are determined by the shape and period of the patterns formed by the first material 162, it is easy to select them appropriately, and the filtering performance is excellent and thus may be applied to various technical fields. . For example, it can be applied as a color filter in an image sensor such as a charge coupled device (CCD), a line sensor such as a crystal sensor, and a color filter in a flat panel display.

Hereinafter, an embodiment of the manufacturing method of the color filter 100 will be described with reference to FIGS. 4A to 4D.

As shown in FIG. 4A, the refractive material layer 260 is formed on the substrate 130. For example, a glass substrate may be used as the substrate 130. The refractive material layer 260 may be formed of a substrate 130 containing amorphous silicon (a-Si) by a deposition process such as plasma-enhanced chemical vapor deposition (PECVD) or sputtering. It can be formed by depositing on). Before forming the refractive material layer 260, a barrier layer 150 is formed by depositing SiO ₂ , Si ₃ N ₄ , Indium-Tin Oxide (ITO), or the like on the substrate 130, and the refractive material layer thereon. 260 may be formed. The barrier layer 150 serves to prevent impurity of the glass substrate employed as the substrate 130 in the molding and recrystallization process described below to be incorporated into the refractive material layer 260 to lower the crystal purity. In addition, the barrier layer 150 may serve to prevent heat transfer to the substrate 130 in a recrystallization process to be described later.

As shown in FIG. 4B, the crystal 210 having the two-dimensional photonic crystal color pattern structure is contacted with the refractive material layer 260 and pressed at a predetermined pressure to supply crystallization energy to the refractive material layer 260. Crystallization energy may be provided by an excimer laser, for example, an XeCl laser, a pulsed excimer laser or the like. The crystallization energy may be, for example, about 150 to 200 mJ / cm ² . Crystallization energy may be provided for example about 250 nanoseconds. The crystallization energy may be provided by one scan, or may be provided by a plurality of scans for a short time. As the amorphous silicon (a-Si) forming the refractive material layer 260 is instantaneously melted by crystallization energy, it is filled with the photonic crystal color pattern structure provided in the mold 210 as shown in FIG. 260 is molded into a two-dimensional photonic crystal color pattern structure determined by the shape of the mold 210. After the supply of crystallization energy is terminated, the amorphous silicon (a-Si) is solidified and the refractive material layer 260 is formed into a photonic crystal layer having a two-dimensional photonic crystal color pattern structure (FIG. 1: 160). At this time, the amorphous silicon (a-Si) constituting the refractive material layer 260 is recrystallized and converted into polysilicon (p-Si: Poly-Silicon) having a small imaginary component value of the refractive index. As the material of the mold 210, a material having a higher melting point than silicon, a low absorption rate of the excimer laser, and a low thermal conductivity may be employed. For example, quartz may be employed as the material of the mold 210.

When the molding and recrystallization process is completed, the mold 210 is spaced apart from the refractive material layer 260 to form a photonic crystal layer 160 having a two-dimensional photonic crystal color pattern structure as shown in FIG. 4D.

In the case of amorphous silicon (a-Si), the refractive index of the imaginary part is large in the short wavelength region, the reflectance decreases due to light absorption, the bandwidth of the color spectrum is widened, and the spectral shift occurs, thereby degrading the color characteristics. Therefore, it is necessary to form the photonic crystal layer 160 of single crystal silicon or polysilicon (p-Si), and forming a single crystal silicon thin film on a glass substrate requires a high technical level. However, according to the manufacturing method of the present invention, amorphous silicon (a-Si) is recrystallized and converted into polysilicon (p-Si) to be easily formed of polysilicon (p-Si) even at a relatively low process level. The photonic crystal layer 160 may be formed. In addition, since the mold 210 serves as a support during the crystallization process, it is possible to prevent deformation of the photonic crystal color pattern structure during the crystallization process. Thus, the process of forming the support layer can be excluded.

Amorphous silicon (a-Si) may contain a few percent of hydrogen, which may be vaporized in the recrystallization process and penetrate the surface of the refractive material layer 260 to damage the two-dimensional photonic crystal color pattern structure. Therefore, before the above-described process of forming and recrystallizing the refractive material layer 260 into a two-dimensional photonic crystal color pattern structure, hydrogen present in the amorphous silicon (a-Si) deposited on the substrate 130 is performed. A dehydrogenation process may be performed to remove the. The dehydrogenation process may be performed, for example, by annealing the substrate 130 on which amorphous silicon (a-Si) is deposited at a temperature of about 300 to 500 degrees for about 2 hours.

In addition, a process of removing foreign matter present on the surface of the photonic crystal layer 160 may be performed. In addition, the concave portion 165 of the photonic crystal layer 160 may be filled with a second material 166 such as PC, PS, PMMA, Si ₃ N ₄ , and SiO ₂ . The material 166 may serve as a protective layer to protect the two-dimensional photonic crystal color pattern structure.

According to a conventional method for manufacturing a photonic crystal color pattern, a black matrix pattern is formed on a substrate and a color pattern corresponding to the R, G, and B regions is formed by a photolithography process. Such a manufacturing method requires about 20 steps of putting a photoresist film on a substrate and forming a pattern, and thus a large burden in terms of cost and environment.

In the method of manufacturing a photonic crystal color pattern using nanoimprint technology, by forming a silicon layer on a substrate, forming a hard mask, patterning the silicon layer by a nanoimprinting process, and etching the silicon layer using a hard mask. A photonic crystal layer is formed. In the case of a manufacturing process based on a single crystal silicon layer, high process technology is required to form a single crystal silicon layer on a substrate. In the case of a manufacturing process based on amorphous silicon, uniform etching must be performed in the etching process in order to obtain a good photonic crystal pattern. However, it is not easy to uniformly etch amorphous silicon. Because amorphous silicon is not crystalline, the bonding energy between silicon and hydrogen contained in the amorphous silicon differs depending on the position. Thus, even if the etching energy provided to the amorphous silicon in the etching process is uniform, the etching amount may be uneven. Such nonuniformity of etching may result in nonuniformity of the photonic crystal color pattern, thereby degrading the quality of the color filter.

However, as described above, according to the manufacturing method according to an embodiment of the present invention, the etching process may be excluded in the process of forming the photonic crystal color pattern structure. Therefore, the precision of the photonic crystal color pattern structure depends on the precision of the mold 210. The mold 210 is very precise, for example, because it is manufactured using a master made very precisely by an electron beam lithography process. Thus, production of color filters of good quality is possible. In addition, since the etching process is excluded and the molding and recrystallization are performed at the same time, the manufacturing process can be greatly simplified, thereby reducing the process cost and time.

5A to 5C, another embodiment of the manufacturing method of the color filter according to the present invention will be described.

As shown in FIG. 5A, the refractive material layer 261 may be formed by coating a silicon-based nanoparticle solution or a polysilane resin on the substrate 130 by, for example, a spin coating process. Of course, before the refractive material layer 261 is formed, SiO ₂ , Si ₃ N ₄ , ITO, or the like is deposited on the substrate 130 to form the barrier layer 150, and the refractive material layer 260 is formed thereon. It may be formed.

As shown in FIG. 5B, the mold 210 having the photonic crystal color pattern structure is contacted with the refractive material layer 261 and pressed at a predetermined pressure to determine the refractive material layer 261 based on the shape of the mold 210. Paper is molded into a two-dimensional photonic crystal color pattern structure. At this time, UV-ray light may be irradiated to the refractive material layer 261 or thermal curing may be performed on the refractive material layer 261. For example, when quartz or a soft mold is employed as the material of the mold 210, UV light may be irradiated through the mold 210, and nickel may be used as the material of the mold 210. If employed, thermal treatment can be performed.

Next, the mold 210 is spaced apart, and as shown in FIG. 5C, the excimer laser is irradiated to the refractive material layer 261 to supply crystallization energy. The crystallization energy instantly melts and solidifies the silicon-based nanoparticles or polysilane resin. At this time, the silicon particles are recrystallized and converted into polysilicon (p-Si) having a small imaginary component value of the refractive index. As a result, a polysilicon (p-Si) based photonic crystal layer (FIG. 1: 160) may be formed.

Before performing the crystallization process, a process for removing impurities remaining in the refractive material layer 261 formed into the two-dimensional photonic crystal color pattern structure may be performed. This process is, for example, it is carried out by oxygen ashing (O ₂ ashing) process.

In addition, before performing the crystallization process, a process of forming a support layer may be performed to prevent the two-dimensional photonic crystal color pattern structure from being deformed during the crystallization process. Referring to FIG. 5C, the support layer 270 may be formed by depositing a support material, such as SiO ₂ , Si ₃ N ₄ , ITO, or Ni, on a two-dimensional photonic crystal color pattern structure for a PECVD process. In addition, when Ni is used as the support material, a process of removing Ni after performing a crystallization process may be performed. Ni may be removed by, for example, a wet strip process in a solution in which nitric acid and water are mixed 1: 1. The support layer 270 may be formed by filling the above-described support material into the recess 165 of the photonic crystal color pattern structure.

In addition, a process of removing foreign matter present on the surface of the photonic crystal layer 160 may be performed. In addition, the concave portion 165 of the photonic crystal layer 160 may be filled with a second material 166 such as PC, PS, PMMA, Si ₃ N ₄ , and SiO ₂ .

As described above, by forming a refractive material layer using a silicon-based nanoparticle solution or a pulley silane resin and forming a photonic crystal layer by a molding process and a crystallization process using a mold, A photonic crystal layer can be formed.

Although embodiments of the method for manufacturing a color filter according to the present invention have been described with reference to the drawings for clarity, this is merely exemplary, and those skilled in the art may have various modifications and equivalent embodiments therefrom. I understand that it is possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

1 is a perspective view showing an example of a color filter manufactured by the method for manufacturing a color filter according to the present invention.

2 is a cross-sectional view of the color filter of FIG.

3 is a plan view of the color filter of FIG.

4A to 4D are views illustrating one embodiment of a method of manufacturing a color filter according to the present invention.

5A to 5C are views for explaining another embodiment of the manufacturing method of the color filter according to the present invention;

<Explanation of symbols for the main parts of the drawings>

100 ... color filter 130 ... substrate

150,250,450 Barrier layer 160 Photonic crystal layer

162 ... First Substance 166 ... Second Substance

210 ... mold 260, 261 ... refractive material layer

270 ... support layer

Claims (15)

Forming a refractive material layer on the substrate; Supplying crystallization energy to the refractive material layer while pressing the refractive material layer by using a mold having a two-dimensional photonic crystal color pattern structure to form the refractive material layer into the two-dimensional photonic crystal color pattern structure; Spaced apart the mold; Method of manufacturing a two-dimensional photonic crystal color filter comprising a. The method of claim 1, Wherein the crystallization energy is provided by scanning an excimer laser at least once on the refractive material layer. The method of claim 1, The refractive material layer is an amorphous silicon layer, the method of manufacturing a two-dimensional photonic crystal color filter is converted into a polysilicon layer by the crystallization energy. The method of claim 3, And a dehydrogenation process for removing hydrogen in the amorphous silicon layer between forming the refractive material layer and recrystallizing. The method according to any one of claims 1 to 4, And forming a barrier layer between the substrate and the refractive material layer. Forming a refractive material layer on the substrate; Pressing the refractive material layer using a mold having a two-dimensional photonic crystal color pattern structure to mold the refractive material layer into the two-dimensional photonic crystal color pattern structure; Spacing the mold; Supplying crystallization energy to the refractive material layer to recrystallize the refractive material layer. The method of claim 6, Wherein the crystallization energy is provided by scanning an excimer laser at least once on the refractive material layer. The method of claim 6, Removing impurities remaining in the refractive material layer formed into the two-dimensional photonic crystal color pattern structure by an oxygen ashing process before performing the recrystallization step; Method of manufacturing a two-dimensional photonic crystal color filter further comprising. The method of claim 8, After removing the impurities, forming a support layer for preventing deformation of the two-dimensional photonic crystal color pattern structure formed on the refractive material layer in the recrystallization process; manufacturing a two-dimensional photonic crystal color filter further comprising Way. 10. The method of claim 9, The forming of the support layer may include depositing at least one support material among SiO 4, Si 3 N 4, ITO, and Ni along the two-dimensional photonic crystal color pattern structure formed on the refractive material layer. Manufacturing method. 10. The method of claim 9, The forming of the support layer may further include filling a support material into a recess of the two-dimensional photonic crystal color pattern structure formed on the refractive material layer. The method according to any one of claims 6 to 11, The refractive material layer is a silicon-based nanoparticle solution, The molding process includes a process of treating or heat treating the refractive material layer with UV light, And the refractive material layer is converted into a polysilicon layer by the crystallization energy. The method of claim 12, And forming a barrier layer between the substrate and the refractive material layer. The method according to any one of claims 6 to 11, The refractive material layer is a polysilane resin, The molding process includes a UV treatment or heat treatment process for molding the polysilane resin, And the refractive material layer is converted into a polysilicon layer by the crystallization energy. The method of claim 14, And forming a barrier layer between the substrate and the refractive material layer.

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