KR20050038243A - Method for manufacturing a wire grid polarizer - Google Patents

Abstract

Disclosed is a method for manufacturing a lattice polarizer that operates in the visible region and can improve polarization efficiency.

In the method of manufacturing a lattice polarizer of the present invention, first, a stamper for manufacturing a lattice polarizer is manufactured, and a lattice polarizer is manufactured using an imprint and sidewall patterning technique based on the manufactured stamper.

Accordingly, a wire lattice polarizing plate having a period of 100 nm and a width of 50 nm is manufactured, and by applying such a polarizing plate to a projection television or the like, a clearer image can be realized.

Description

Method for manufacturing a grid polarizer {Method for manufacturing a wire grid polarizer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lattice polarizer, and more particularly, to a method of manufacturing a lattice polarizer that operates in the visible region while improving polarization efficiency.

One of the most widely used microstructure fabrication techniques to date is photolithography, which uses a project-printing system to repeatedly reduce pre-designed circuitry on a substrate coated with a photoresist thin film. It is a method of forming a pattern.

At this time, the size of the pattern is limited by the optical diffraction phenomenon, the resolution is almost proportional to the wavelength of the light used. Therefore, the smaller the wavelength of the light, the higher resolution patterns can be formed. In recent years, the development of an optical transfer method using short-wavelength light sources such as EUV (Extreme Ultra Violet) and soft X-ray has been actively studied worldwide. .

In general, the performance of a wire grid is mainly determined by the distance between the line and the center of the line, that is, the period and the wavelength of the incident wave. For example, when the grating period becomes longer than the wavelength of the incident wave, the grating acts as a diffraction grating. This diffracts irrespective of polarization to form diffraction interference fringes due to a theoretically well known phase difference. On the other hand, when the lattice spacing, i.e., the period is shorter than the wavelength of the incident wave, the grating acts as a polarizer, as shown in FIG. The polarized wavelength (S wave) is transmitted.

Typically, a lattice polarizer used in a projection television or the like is mainly used in the far-infrared region because the lattice period must be shortened to polarize light having a short wavelength. That is, in order to use it as a polarizer with high polarization characteristics (ER: Extinction Ratio) for three primary colors of red (R), green (G), and blue (B) including blue (B), A grating having a cycle of 0.1 μm or less is desired.

In recent years, with the development of semiconductor manufacturing technology, a line width of about 0.1 μm can be formed. Therefore, when such a line width is used, the lattice period of the lattice polarizer is 0.2 m. For example, when using an interference effect using a short wavelength argon (Ar) laser, the lattice period can be up to 200 nm. To form a finer pattern, a stepper using a shorter wavelength (DUV) or an EUV wavelength or a shorter wavelength laser is used. On the other hand, a method of forming a fine pattern using lithography using an electron beam or an interferometer using an atomic beam is being studied, but such a method has a limited size and is very complicated and requires expensive equipment. Etc. have severe restrictions on commercial access.

As described above, when the grid pattern is formed on the grid polarizer using conventional optical transfer method or electron beam, the nonuniformity of the laser power and the surrounding environment (for example, vibration, air flow, noise, reflection, etc.) There is a problem in that it is difficult to form a predetermined uniform pattern due to the influence of the filament life and the slowness of the pattern formation speed.

Accordingly, an object of the present invention is to provide a method for manufacturing a lattice polarizing plate capable of minimizing the period of the lattice without using a conventional optical transfer method.

According to a preferred embodiment of the present invention for achieving the above object, a wire lattice polarizing plate manufacturing method comprises the steps of preparing a stamper for producing a lattice polarizing plate; And manufacturing a grating polarizer using an imprint and sidewall patterning technique based on the manufactured stamper.

The manufacturing of the stamper for manufacturing the lattice polarizer includes: sequentially depositing a silicon dioxide layer and a chromium layer on the first substrate; Exposing the photoresist mask to form a predetermined pattern; Sequentially etching the chromium layer and the silicon dioxide layer using the patterned photoresist as a mask, and removing the chromium layer to complete a preliminary stamper; Sequentially depositing a silicon dioxide layer and a polymer on a second substrate; Imprinting the polymer deposited on the second substrate using the preliminary stamper to form a predetermined pattern; Etching the silicon dioxide layer using the patterned polymer as a mask until the second substrate is exposed; And removing the patterned polymer to complete the stamper for manufacturing the lattice polarizer.

The manufacturing of the grating polarizer may include sequentially depositing an aluminum layer, a silicon dioxide layer, a chromium layer, and a polymer on a third substrate; Imprinting a polymer deposited on the third substrate by using the grid grating stamper to form a predetermined pattern; Sequentially etching the chromium layer and the silicon dioxide layer using the patterned polymer as a mask; Removing the patterned chromium layer and then depositing a silicon lightride layer on the aluminum layer and the patterned silicon dioxide layer; Over-etching the silicon nitride layer so that the top of the patterned silicon dioxide layer is completely exposed, and then etching and removing the patterned silicon dioxide layer; And etching the aluminum layer using the over-etched silicon nitride layer as an etch mask, and then removing the over-etched silicon nitride layer to complete a lattice polarizer.

By such a manufacturing method, a wire lattice polarizing plate having a period of 100 nm can be manufactured, and more improved polarization characteristics can be expected.

Hereinafter, with reference to the accompanying drawings will be described in detail a method for producing a grid polarizer of the present invention.

First, prior to explaining this, the nanoimprint used in the present invention will be briefly described.

Nanoimprint technology is a technique proposed to overcome the limitations of the formation of fine patterns as in the prior art, a nano device fabrication method introduced by Professor Stephen Y. Chou of the United States in the mid-1990s, having a low productivity It is attracting attention as a technology to replace electron beam lithography or expensive optical lithography.

Nanoimprint technology is an embossing technique for lithography that is used for mass production of polymer material products with microscale patterns such as compact discs (CD). The core of the nanoimprint is to prepare a stamp (or mold) having a nanoscale structure by using electron beam lithography or other methods, and to imprint the structure of the nanoscale by imprinting the fabricated stamp onto a polymer thin film and repeating the same. By overcoming the problem of productivity of electron beam lithography.

Currently, the grid polarizers used in projection televisions have a period of about 140 nm, which is more expensive than polymer-based polarizers but is increasingly used because of their superior performance. In general, as the lattice period of the grating polarizer decreases, the polarization characteristic is improved exponentially. That is, as shown in Figure 2, using aluminum (Al) as a metal material, the height of the lattice is 140nm, assuming that the line width of aluminum is half the period, it can be seen that the polarization efficiency is improved as the period is shorter have. For example, if the period of 140 nm is reduced to a period of 100 nm, the polarization efficiency is improved by about three times. As shown in FIG. 2, in order for the polarization efficiency to be 10,000 or more in red (R = 650 nm), green (G = 550 nm) and blue (B = 450 nm), the period of the grating must be 100 nm or less and the line width should be about 50 nm. do.

Therefore, the present invention proposes a method for manufacturing a lattice polarizer that can improve the polarization efficiency by reducing the lattice period and line width using nanoimprint.

The present invention is largely divided into two process processes, namely, a stamper used for manufacturing a grid polarizer, that is, a process of manufacturing a mold, and imprinting using the mold, and patterning side-walls combined with patterning. The process consists of manufacturing a lattice polarizer.

First, a method of manufacturing a stamper used to manufacture a grid polarizer is described.

3A to 3J are schematic views illustrating a method of manufacturing a stamper used to manufacture a lattice polarizer according to an exemplary embodiment of the present invention.

First, a silicon dioxide (SiO ₂ ) layer 13 and a chromium (Cr) layer 15 are sequentially deposited on the silicon substrate 11 (FIG. 3A).

Subsequently, a photoresist mask 17 is placed on the chromium layer 15 and then exposed to laser interference or electron beam to form a pattern of 200 nm period (FIG. 3B). At this time, the width of the pattern is maintained at 50 nm.

Then, the photoresist mask 17 exposed by the laser interference or electron beam is removed, and then the chromium layer 15 is etched using the unremoved photoresist mask (FIG. 3C).

In addition, the silicon dioxide layer 13 under the etched chromium layer 15 is also continuously etched (FIG. 3D).

Next, the preliminary stamper is completed by removing the chromium layer 13 using a chromium etchant (FIG. 3E). At this time, the preliminary stamper is cleaned with a surface treatment agent to minimize contamination.

Next, the silicon dioxide layer 23 and the polymer 25 are sequentially deposited again on another silicon substrate 21 (FIG. 3F).

The polymer 25 deposited on the silicon substrate 21 is imprinted using the preliminary stamper 27 completed in FIG. 3E (FIG. 3G).

Then, by separating the preliminary stamper 27 from the polymer 25, a pattern is formed on the polymer 25 deposited on the silicon substrate 21 (FIG. 3H). At this time, the pattern formed on the polymer 25 is reversely transferred to the pattern formed on the preliminary stamper 27. That is, the width of the pattern formed on the polymer 25 is maintained at 150nm.

Using the patterned polymer 25 as a mask, the silicon dioxide layer 23 is etched until the silicon substrate 21 is exposed (FIG. 3I).

Next, by removing the patterned polymer 25, a stamper for the lattice polarizer having a pattern width of the silicon dioxide layer 23 of 150 nm and a period of 200 nm is completed (FIG. 3J).

4A to 4J are schematic views illustrating a method of manufacturing a lattice polarizer using the stamper manufactured in FIG. 3J.

First, an aluminum (Al) layer 33, a silicon dioxide (SiO ₂ ) layer 35, a chromium (Cr) layer 37 and a polymer 39 are sequentially deposited on the transparent glass substrate 31 (Fig. 4a). At this time, the polymer 39 is preferably made of a material suitable for imprint by the stamper for the lattice polarizer plate completed in Figure 3j.

The polymer 39 deposited on the glass substrate 31 is imprinted using the stamper for the lattice polarizer plate completed in FIG. 3J (FIG. 4B). Accordingly, the pattern formed on the stamper for the lattice polarizer is transferred to the polymer 39 in reverse. Therefore, the width of the pattern formed on the polymer 39 deposited on the glass substrate 31 is maintained at 50 nm, and the period is 200 nm.

Next, using the patterned polymer 39 as a mask, the chromium layer is exposed until the silicon dioxide layer 35 is exposed by optimizing variables such as mixing ratio, pressure, power, and time of an appropriate amount of Cl2 and O2 gas. (37) is etched (FIG. 4C).

Subsequently, the silicon dioxide layer 35 is etched until the aluminum layer 33 is exposed by optimizing variables such as mixing ratio, pressure, power, time, etc. of SiO 2, CHF 3, CF 4, and O 2 gas (FIG. 4D). . Here, when etching the chromium layer 37 and the silicon dioxide layer 35, it is preferable to etch until there is no residue for chromium and silicon dioxide. This is because if the chromium layer 37 and the silicon dioxide layer 35 are present after etching, all the silicon nitrite layers will come off when later etching the silicon nitride (Si3N4) layer.

As such, when the chromium layer 37 and the silicon dioxide layer 35 are etched, the silicon dioxide layer deposited on the glass substrate 31 by removing the patterned chromium layer 37 using a chromium etchant. A pattern is formed at 35 (Fig. 4E). At this time, the width of the pattern formed on the silicon dioxide layer 35 is maintained at 50nm.

Next, a silicon nitride (Si 3 N 4) layer 41 is deposited on the aluminum layer 33 deposited on the glass substrate 31 and the patterned silicon dioxide layer 35 (FIG. 4F). Accordingly, the silicon nitride layer 41 is deposited on the aluminum layer 33 and the patterned silicon dioxide layer 35. In particular, the silicon nitride layer 41 deposited on the patterned silicon dioxide layer 35 has a convex shape. In contrast, the silicon nitride layer 41 deposited on the aluminum layer 33 is deposited by the height of the silicon dioxide layer 35.

When all of the silicon nitride layer 41 is deposited, the silicon nitride layer overetched the silicon nitride layer 41 and positioned on both sidewalls of the patterned silicon dioxide layer 35. The width of 41 is maintained at 50 nm, while the silicon nitride layer 41 deposited over the patterned silicon dioxide layer 35 is all removed. At this time, the height of the silicon nitride layer 41 positioned on both sidewalls of the patterned silicon dioxide layer 35 is preferably maintained at 40 ~ 50nm. Accordingly, a silicon nitride pattern having a pattern width of 50 nm is formed on the aluminum layer 33, and the silicon nitride pattern is used as an etching mask for etching the aluminum layer 33.

Subsequently, the patterned silicon dioxide layer 35 is etched and removed using a BOE (Buffered Oxide Etch) solution containing Hydro Fluoride (HF) (FIG. 4H). At this time, the patterned silicon dioxide layer 35 is different in the etching rate according to the growth temperature when the silicon nitride layer 41 is deposited.

For example, when the silicon nitride layer 41 is deposited at 800 ° C., the etching proceeds rapidly at a high concentration of hydrofluoride (approximately 49% HF) at about 100 nm / min, whereas when deposited at 1000 ° C. The etching proceeds slowly at 14 nm / min. In addition, when the silicon nitride layer 41 is deposited at 300 ° C., etching proceeds very slowly at 10 nm / min in BOE (10: 1).

Next, the aluminum layer 33 is anisotropically etched using BCl 3 gas or the like using the silicon nitride pattern as an etching mask so that the direction of etching proceeds vertically (FIG. 4I). In this case, etching of the aluminum layer 33 may be performed until the organic substrate is exposed.

Then, the silicon lightride pattern is etched and removed using a high concentration hydrofluoride (HF) or a phosphoric acid solution (FIG. 4J). At this time, an aluminum pattern 33 is formed on the glass substrate 31. In this case, the aluminum pattern 33 is preferably maintained at a height of 170 nm, a width of 50 nm, and a period of 100 nm.

Therefore, an aluminum pattern is formed on the transparent glass substrate through such a process, thereby completing a grid polarizer for polarizing incident light.

By applying to a projection television using a grating polarizer having a period of 100nm and a width of 50nm as described above, it is expected that the polarization efficiency can be significantly improved to realize a clearer image.

As described above, according to the method of manufacturing the grating polarizer of the present invention, the period and the pattern width may be more finely formed to improve the polarization efficiency and operate in the visible light region.

In addition, by using imprint lithography instead of using the conventional optical transfer method, it is possible to manufacture a lattice polarizer with low process cost and simplicity.

1 is a view for explaining the concept of a typical grating polarizer.

2 is a graph showing the relationship between the lattice period and polarization efficiency.

3A to 3J schematically illustrate a method of manufacturing a stamper used to manufacture a lattice polarizer according to a preferred embodiment of the present invention.

4A to 4J are schematic views illustrating a method of manufacturing a lattice polarizer using the stamper manufactured in FIG. 3J.

Claims (15)

In the method of manufacturing a grid polarizer, Manufacturing a stamper for manufacturing a lattice polarizer; And Manufacturing a grating polarizer using an imprint and sidewall patterning technique based on the manufactured stamper Grid polarizer manufacturing method comprising a. The method of claim 1, wherein the manufacturing of the stamper for manufacturing the lattice polarizer is performed. Sequentially depositing a silicon dioxide layer and a chromium layer on the first substrate; Exposing the photoresist mask to form a predetermined pattern; Sequentially etching the chromium layer and the silicon dioxide layer using the patterned photoresist as a mask, and removing the chromium layer to complete a preliminary stamper; Sequentially depositing a silicon dioxide layer and a polymer on a second substrate; Imprinting the polymer deposited on the second substrate using the preliminary stamper to form a predetermined pattern; Etching the silicon dioxide layer using the patterned polymer as a mask until the second substrate is exposed; And Removing the patterned polymer to complete a stamper for manufacturing the grating polarizer Grid polarizer manufacturing method comprising a. The method of claim 2, wherein the pattern formed on the preliminary stamper is transferred to the pattern formed on the stamper for manufacturing the lattice polarizer. The method of claim 2, wherein the pattern formed on the preliminary stamper has a period of 200 nm and a pattern width of 50 nm. The method of claim 2, wherein the pattern formed on the stamper for manufacturing the lattice polarizer has a period of 200 nm and a pattern width of 150 nm. The method according to claim 2, wherein the first and second substrates are made of a silicon material. The method according to claim 2, wherein the photoresist is exposed by either laser interference or electron beam. The method of claim 1, wherein the manufacturing of the wire grid polarizer is performed. Sequentially depositing an aluminum layer, a silicon dioxide layer, a chromium layer and a polymer on a third substrate; Imprinting a polymer deposited on the third substrate by using the grid grating stamper to form a predetermined pattern; Sequentially etching the chromium layer and the silicon dioxide layer using the patterned polymer as a mask; Removing the patterned chromium layer and then depositing a silicon lightride layer on the aluminum layer and the patterned silicon dioxide layer; Over-etching the silicon nitride layer so that the top of the patterned silicon dioxide layer is completely exposed, and then etching and removing the patterned silicon dioxide layer; And Etching the aluminum layer using the over-etched silicon nitride layer as an etch mask, and then removing the over-etched silicon nitride layer to complete a lattice polarizer. Grid polarizer manufacturing method comprising a. The method according to claim 8, wherein the third substrate is made of a transparent glass material. The method of claim 8, wherein the pattern formed on the polymer has a 200nm period and a 50nm pattern width. The method of claim 8, wherein the chromium layer is etched using a mixing ratio of Cl 2 gas and O 2 gas, pressure, power, and time as variables. The method of claim 8, wherein the silicon dioxide layer is etched using a mixing ratio, pressure, power, and time of SiO 2, CHF 3, or CF 4, and O 2 gas as variables. The method of claim 8, wherein the chromium layer and the silicon dioxide layer are etched until there is no residue for chromium and silicon dioxide at the bottom. The line of claim 8, wherein after the silicon nitride layer is over-etched, the silicon nitride layer positioned on both sidewalls of the patterned silicon dioxide layer has a width of 50 nm and a height of 40 to 50 nm. Grid polarizing plate manufacturing method. The method of claim 8, wherein the aluminum layer is etched by BCl 3 gas.