CN101798059B - Production method of silicon-based nanopore - Google Patents

Abstract

The invention provides a production method of a silicon-based nanopore, which comprises the following steps of: 1. covering a protecton material and a top protection material on a silicon substrate, and machining a pattern which needs to be etched on the silicon substrate onto the two layers of protection materials with a micro-production technology, wherein the depth of the pattern reaches the surface of the bottom of the silicon substrate; 2. etching a perpendicular columnar pore on the surface of the bottom of the silicon substrate with a deep reaction ion etching DRIE method; 3. coating photoresist on the surface of the columnar pore; and 4. continually downwards corroding from the end of the columnar pore with potassium hydroxide alkaline solution by means of wet etching, so that an included angle between a corroded inclined plane and the horizontal plane is 53.7 degrees, so as to obtain the silicon-based nanopore with controllable size. The production method provides technical support for the surface controlling technology of atomic beam and the other nanometer machining technologies, and plays a role in promoting.

Description

A method for fabricating silicon-based nanopores

technical field

The invention relates to the field of silicon surface processing technology and deep processing technology, in particular to a method for making silicon-based nanoholes for atomic lithography.

Background technique

In the field of nanofabrication, the application of atomic optics is an emerging field of research that offers a variety of methods for fabricating nanoscale materials. A great deal of research in fundamental atomic optics has provided many different ways of manipulating free neutral atoms. The main direction of research is the control of the movement of atoms as they approach the surface, with the aim of constructing arbitrary nanostructures on the substrate surface. Fabricating nanopores of different sizes, nanoscale stripes, lattices, or desired specific patterns can be used to control the movement of atoms.

At present, there is no very good method for making silicon-based nanopores, which is mainly determined by the characteristics of silicon-based nanopores themselves. The thickness of ordinary silicon wafers used in the semiconductor industry is about a few hundred microns. To form nanometer-scale holes or stripes on silicon wafers, very precise technical control is required. The existing nanopores or nanosieves are mainly produced by synthetic methods. Mintova et al. used the in-situ hydrothermal crystallization method to obtain Silicalite-1 nano-molecular sieve grains with uniform particle size distribution for the first time [Document 1: Mintova S, Mo S, Bein T.[J].Nanosized AlPO4-5 molecular sieves and Ultrathin films prepared by microwave synthesis.Chem.Mater, 1998,10(12):4030～4036], the method is simple in operation and does not require special equipment, but the molecular sieve crystal size and orientation control of the prepared method have poor reproducibility, To obtain a dense and pinhole-free film, a thickness of at least several microns is required, which leads to cracking and even falling off when the temperature changes. Xu et al. successfully synthesized NaA-type molecular sieve membranes using microwave heating technology [Document 2: Xu X C, Yang W S, Liu J, et al.[J].Synthesis of high-permeance NaA zeolite membrane by microwave heating Adv. Mater, 2000, 12(3): 195～197], this method can increase the crystallization rate and reduce the crystal size to a certain extent, but it is prone to local accumulation of molecular sieves, and it is difficult to control the formation of large-area uniform molecular sieves on the surface of the support substrate. And dense molecular sieve membrane.

Contents of the invention

In order to overcome the above-mentioned defects in the prior art, the object of the present invention is to provide a method for fabricating silicon-based nanopores, which can control the movement of atoms when they approach the surface.

In order to achieve the above object, the technical solution of the present invention is achieved in that:

A method for making silicon-based nanopores, comprising the following steps:

1. Cover the protective material 2 and the top protective material 3 on the silicon substrate 1. The protective material 2 adopts a sputtered chromium layer with a thickness of 300nm, and the top protective material 3 adopts a sputtered aluminum layer with a thickness of 300nm. The technology processes the pattern that needs to be etched on the silicon substrate 1 onto two layers of protective materials, and the depth of the pattern reaches the surface of the silicon substrate 1;

Two, use deep reactive ion etching DRIE method to etch vertical columnar holes on the surface of silicon substrate 1, the depth of etching depends on the thickness of the silicon wafer used and the distance between the silicon nanoholes to be made, according to The characteristics of silicon anisotropic wet etching and the distance between the silicon nanopores to be fabricated can obtain the depth of wet etching, and the depth of deep reactive ion etching DRIE etching is the thickness of the silicon wafer minus the wet etching depth;

3. Coating photoresist 5 on the surface 6 of the columnar hole;

4. Wet etching is adopted, using a potassium hydroxide alkaline solution with a concentration of 30%, to continue etching from the end of the columnar hole downwards, so that the angle between the etched inclined plane 4 and the horizontal plane is 53.7°, and finally a controllable size is obtained. Silicon nanopores7.

The manufacturing method of the present invention avoids the traditional synthesis method, adopts the characteristics of combining deep reactive ion etching (DRIE) dry etching and wet etching, and manufactures silicon nanopores on ordinary silicon wafers. In the manufacturing method of the present invention, the top protective material 3 can avoid etching the protective material 2 in the dry etching, and the protective material 2 can avoid the corrosion of the silicon substrate 1 under the protective layer by the solution in the wet etching. There is a protection layer 5 on the surface 6 of the columnar hole to prevent the silicon material on the side from being corroded during the wet etching process.

Description of drawings

Fig. 1 is a sectional view of the manufacturing process of the present invention.

Fig. 2 is a front view of the manufacturing process of the present invention.

Fig. 3 is a top view of the manufacturing process of the present invention.

Fig. 4 is a schematic diagram of the structure of the silicon-based nanopore produced by the present invention.

Detailed ways

The principle of the present invention will be described in detail below in conjunction with the accompanying drawings.

A method for making silicon-based nanopores, comprising the following steps:

1. Referring to FIG. 1, the protective material 2 and the top layer protective material 3 are covered on the silicon substrate 1, the purpose is to form a silicon etching window with a protective layer, so that the protected The part is not corroded, the protective material 2 adopts a sputtered chromium layer with a thickness of 300nm, and the top protective material 3 adopts a sputtered aluminum layer with a thickness of 300nm. The graphics are processed on two layers of protective materials, and the depth of the graphics reaches the surface of the silicon substrate 1;

2. Referring to FIG. 2, vertical columnar holes are etched on the surface of the silicon substrate 1 by deep reactive ion etching (DRIE). The depth of etching depends on the thickness of the silicon wafer used and the gap between the silicon nanopores According to the characteristics of silicon anisotropic wet etching and the distance between the silicon nanopores to be fabricated, the depth of wet etching can be obtained, and the depth of wet etching can be obtained by subtracting the thickness of silicon wafer from the depth of wet etching. Etching depth of DRIE etching;

3. Referring to Fig. 1 and Fig. 2, a photoresist 5 is coated on the surface 6 of the columnar hole to prevent the silicon material on the side from being corroded during the wet etching process;

4. Referring to Fig. 4, wet etching is adopted, using a potassium hydroxide alkaline solution with a concentration of 30%, to continue etching downward from the end of the columnar hole, so that the angle between the etched inclined plane 4 and the horizontal plane is 53.7°, and finally A size-controllable silicon nanopore 7 is obtained.

Claims (1)

1. A method for preparing silicon-based nanopores, comprising the following steps: 1. Cover the protective material (2) and the top protective material (3) on the silicon substrate (1). The protective material (2) is a sputtered chromium layer with a thickness of 300nm. The top protective material (3) is sputtered Aluminum layer with a thickness of 300nm, using microfabrication technology to process the pattern to be etched on the silicon substrate (1) onto two layers of protective materials, and the depth of the pattern reaches the surface of the silicon substrate (1); 2. Use deep reactive ion etching to etch vertical columnar holes on the surface of the silicon substrate (1). The etching depth depends on the thickness of the silicon wafer used and the distance between the silicon nanoholes to be fabricated. According to the characteristics of silicon anisotropic wet etching and the distance between the silicon nanopores to be fabricated, the depth of wet etching can be obtained, and the depth of deep reactive ion etching is the thickness of silicon wafer minus the depth of wet etching; 3. Apply photoresist (5) on the surface (6) of the columnar hole; 4. Wet etching is adopted, and the potassium hydroxide alkaline solution with a concentration of 30% is used to continue etching downward from the end of the columnar hole, so that the angle between the etched inclined surface (4) and the horizontal plane is 53.7°, and the final size can be obtained. controlled silicon nanopores (7).

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