Method for preparing substrate with periodical structure

Abstract

A method for preparing a substrate with periodical structure, comprising the following steps: (A) providing a substrate and plural nano-sized balls, wherein the nano-sized balls are arranged on the surface of the substrate; (B) depositing a cladding layer on partial surface of the substrate and the gaps between the nano-sized balls; (C) removing the nano-sized balls; (D) etching the substrate by using the cladding layer as a mask; and (E) removing the mask to form a periodical structure on the surface of the substrate. In the present invention, the nano-sized balls are used as a template for forming the mask. Hence, compared with the lithography, when the method of the present invention is used to prepare a substrate with a periodical structure, the duration of the process and the manufacturing cost can be decreased.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a method for preparing a substrate with a periodical structure and, more particularly, to a method, which can prepare a substrate with a periodical structure in a rapid and inexpensive way and protect the substrate from damage.[0003]2. Description of Related Art[0004]A photonic crystal is a periodical structure, which can control and manipulate the flow of light having a certain frequency range, and also can prevent the propagation of light having other frequency ranges. The photonic crystals work at optical wavelengths, so the photonic crystals have to be formed of a periodic sub-micro sized or nano sized structure. Currently, the photonic crystals can be applied widely in the fields of optical communications and optical calculators, and also applied to photoelectric devices to improve the efficiency thereof.[0005]The photonic crystals are generally manufactured by patterning a substrat...

AI Technical Summary

Benefits of technology

[0011]The object of the present invention is to provide a method for preparing a substrate with a periodical structure formed thereon, in order to reduce the time and cost of production, and also prevent the substrate from being damaged.

[0013]According to the method of the present invention, the nano-sized balls arrange automatically and uniformly on the surface of the substrate. The well-arranged nano-sized balls can serve as a template for forming an etching template, to replace the process of photolithography. Because the expensive photo-mask with sub-micro size is not needed, the manufacturing cost of the substrate with the periodical structure can be reduced. Therefore, the method of the present invention can prepare the substrate with the periodical structure in a rapid and inexpensive way. In addition, the material used in the present invention can be obtained very easily, so the method of the present invention is suitable for forming the substrate with the periodical structure at a large scale.

[0017]According to the method of the present invention, step (A) of arranging the nano-sized balls on the surface of the substrate may comprise the following steps: (A1) providing the substrate, and a colloid solution in a container, wherein the colloid solution comprises the nano-sized balls and a surfactant; (A2) placing the substrate in the container, and the colloid solution covering the surface of the substrate; and (A3) adding a volatile solution into the container to obtain the substrate with the nano-sized balls formed thereon. The volatile solution can increase the vaporizing rate of the solution contained in the container. In addition, the nano-sized balls are arranged in nano-sized ball layers. Preferably, the nano-sized balls are arranged into one layer of nano-sized ball layer.

[0018]According to the method of the present invention, the process of dry etching or wet etching may be used for etching the substrate in the step (D). Preferably, the process of wet etching is used, wherein an etching buffer is used to etch the substrate. The type of the etching buffer is determined by the material of the substrate and the cladding layer. The etching buffer may be a general acidic or alkaline etching buffer. The acidic etching buffer may comprise an acidic solution, an alcohol, and water. Preferably, the acidic solution is HF, BOE which is a solution containing HF and NH4F, HCl, HNO3, H2PO4, H2SO4, CH3COOH, or a combination thereof, or the acidic solution is Amine Callates containing ethanolamine, gallic acid, water, hydrogen peroxide, and a surfactant. In addition, the alkaline solution is a solution of NaOH, KOH, NH4OH, CeOH, RbOH, (CH3)4NOH, C2H4(NH2)2, or N2H4, preferably. Furthermore, the alcohol is ethanol or isopropanol, preferably. Because the process of wet etching is used in the method of the present invention, it is possible to protect the substrate from damage.

[0023]According to the method of the present invention, the nano-sized balls can serve as a template for forming an etching template. Hence, the photolithography process can be replaced by the process of forming the nano-sized ball layer. At the same time, the wet etching process is used in the present invention to etch the substrate, so it is possible to reduce the probability of damaging the substrate and obtain a substrate with a uniform periodical structure. Therefore, by using the method of the present invention, the substrate can be patterned to form the periodical structure thereon in a simple, inexpensive, and rapid way.

Problems solved by technology

However, high-energy engraving process has disadvantages of high manufacturing cost and low production capacity.

Although nano-imprinting technology has lower manufacturing cost and higher production capacity than high-energy engraving process, it still cannot meet the requirements for low manufacturing cost and high production capacity.

Although the method of dry etching can produce a substrate having a periodical structure with uniform and regular micro-cavities, there are still some disadvantages with the aforementioned process.

First, the manufacturing cost of photolithography is high and the production rate is low.

However, the photo-mask with sub-micro size is very expensive, and the manufacturing cost of the photo-mask is even more expensive when a periodical structure with a size of 500 nm or less is desired.

In addition, the RIE machine is expensive, the RIE process is slow, and the substrate is damaged easily when the RIE process is used.

The wet etching process can protect the substrate from damage and the surface of the patterned substrate is a natural lattice plane, but the uniformity of the periodical structure is not good enough if the parameter of the wet etching process is not controlled properly.

In addition, the photolithography is still performed in the aforementioned process, so the problems of high manufacturing cost and low production rate still exist.

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