KR100638091B1 - Process for nanoparticle patterning and preparation of sintered body using same - Google Patents

Abstract

The present invention relates to a nanoparticle patterning and a method for producing a sintered body using the same, comprising the steps of: a) making polydisperse nanoparticles into a bipolar charge; b) extracting monodisperse nanoparticles of a desired size by adjusting the center electrode of a differential mobility analyzer (DMA); c) placing the deposition substrate on which the desired photoresist pattern is formed on the center electrode of the electrostatic deposition apparatus and applying a voltage to the center electrode; d) injecting charged monodisperse nanoparticles into the electrostatic deposition apparatus and inducing deposition on the substrate by an electric field generated between the voltage of the center electrode and the grounded voltage of the outer cylinder; And e) a nanoparticle patterning method comprising the step of removing the photoresist pattern on the substrate and a method for producing a nanoparticle sintered body comprising heat-treating the nanoparticle pattern prepared by the above method. The method according to the present invention reduces the number of noise particles deposited outside the pattern to the ultimate level, and its productivity, reproducibility, and portability to other technologies and scalability are excellent, and the method of manufacturing the nanoparticle assembly according to the present invention reduces the line width. It is effective and has economic and time advantages.

Description

Nanoparticle patterning method and manufacturing method of sintered body using the same {PROCESS FOR NANOPARTICLE PATTERNING AND PREPARATION OF SINTERED BODY USING SAME}             

1 is a schematic diagram of a nanoparticle classification and electrostatic deposition process according to the present invention.

2 is a schematic diagram of an electrostatic deposition process of nanoparticles according to the present invention.

Figure 3 schematically illustrates an electro-static precipitator (ESP) suitable for the practice of the present invention.

4 and 5 are low and high resolution scanning electron microscope (SEM) photographs of the micrometer linewidth pattern structure prepared in an embodiment of the present invention.

6 and 7 are SEM photographs of the 100 nm line width nanoparticle structures prepared in Examples of the present invention, and SPM (scanning probe microscope) non-contact scanning photographs of the nanoparticle structures having a 100 nm line width at 800 nm.

8 and 9 are SEM photographs and SPM non-contact scanning photographs of dot-shaped sintered bodies of the nanoparticle assembly structure according to Example 2 of the present invention.

The present invention relates to a nanoparticle patterning method and a method for producing a sintered body using the same.

The fabrication method of micro and nano-sized structures can be divided into bottom-up and top-down methods, but most of the series of micro device manufacturing processes currently used are top-down methods. That's the way. Conventional top-down systems provide new functionality as devices by using the macroscopic physical properties of each material in a multi-layered, multi-stage structure. In contrast, the nanoparticle assembly device manufactured by the bottom-up method is a concept that each nanoparticle, which is a component thereof, has a role as a direct device, and is distinguished from the top-down device in terms of the function of the component and the function of the assembly. .

The core technology required for fabricating devices using functional nanoparticles in such a bottom-up method is nanoparticle growth control, manufacturing and position control, that is, nanoparticle patterning technology. Nanoparticle patterning refers to depositing a material made of nano size represented by nanoparticles, nanotubes, nanowires, etc. in a desired position or obtaining an assembly composed of nanoparticles. Different from the macroscopic properties of quantum materials, quantum devices, single electron transistors, This technology can be applied to tera-level memory devices and high-performance gas sensors.

Recently, nanoparticle technology has been actively applied in micro, nano structure or ultra fine pattern processing, mainly in the United States and Europe. Techniques in this field introduced to date include method using particle beams, contact charging, electron or ion beams, and direct manipulation of a scanning probe microscope (SPM). In addition, a process of generating and patterning several nanoscale nanoparticles using several micro electrostatic spray nozzles, using a chemical colloid method, LB (Langmuir-Blodgett) method, and self-assembled monolayer method Methods of forming nanostructures with structures and molecular arrangements have been studied.

The University of Michigan in the United States developed a direct pattern experiment using laser-induced particle beams, and the German Fissan group used linear pattern deposition of vapor phase nanoparticles with substrate charge through contact with micro-sized metal tips. . Neither the University of Michigan nor the Pisan group found a reliable result, as the overcoming of the diffusivity of nanoparticles was poorly achieved. There was little. Recently, the Whitesides Group of Harvard University in the United States succeeded in patterning microparticles with large-area contact charge using PDMS (polydimethylsiloxane) soft mold. This is a micro-patterning which shows some uniform reproducibility in a large area for micro particles by applying only the improvement of contact reproducibility of the substrate and mold, which is an advantage of the soft lithography technique, and the selectivity of particle pattern deposition, which is an advantage of the conventional contact charge technique. .

However, unlike micro-sized particles, nanoparticles less than 100 nm intensify the effect of diffusion force, which affects many processes as important variables, resulting in improved minimum dimension and noise particles. There are a number of problems to be solved, such as minimizing the size, securing reproducibility and productivity, and improving pattern uniformity.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to implement a nanoparticle patterning method of high precision and high efficiency.

Another object of the present invention is to provide a method for producing a nanoparticle sintered body having excellent line width reduction effect using such a nanoparticle pattern.

In order to achieve the above object, the present invention comprises the steps of: a) making the polydisperse nanoparticles into a bipolar charge state; b) extracting monodisperse nanoparticles of a desired size by adjusting the center electrode of a differential mobility analyzer (DMA); c) placing the deposition substrate on which the desired photoresist pattern is formed on the center electrode of the electrostatic deposition apparatus and applying a voltage to the center electrode; d) injecting charged monodisperse nanoparticles into the electrostatic deposition apparatus and inducing deposition on the substrate by an electric field generated between the voltage of the center electrode and the grounded voltage of the outer cylinder; And e) removing the photoresist pattern on the substrate.

In particular, the deposited nanoparticles are induced by the electric field generated between the voltage applied to the center electrode of the electrostatic deposition apparatus and the grounded voltage of the outer cylinder, and the deposition is performed. Charged nanoparticles are induced into a non-homogenous electric field by pattern deposition through a photosensitive layer used as a homogeneous electric field and a soft mask. The center electrode voltage of the electrostatic deposition apparatus is related to the deposition efficiency and deposition geometry of the nanoparticles, and the center electrode voltage should be determined in consideration of the deposition efficiency and the formation of dendritic aggregates. The center electrode voltage is preferably selected in the range of -10 to +10 kV.

In addition, in order to achieve the above another object, the present invention provides a method for producing a nanoparticle sintered body comprising the heat treatment of the nanoparticle pattern produced by the above method.

The heat treatment process follows a sintering process of a general nanostructure. For example, when the sintering of the nanoparticles is carried out in the heat treatment process to the tube, the sintering of the nanoparticles deposited with the line width of the soft mask proceeds, resulting in a volume change in three directions, resulting in a line width reduction effect of 10 to 40%. Appears. In particular, this technique is preferable in terms of its mechanism, because it is more effective and shows optimum results for the production of dot-shaped structures. In the heat treatment step, the temperature is preferably 200 to 300 ° C., and the heat treatment time is 100 to 150 minutes.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

<Example 1>

Polydisperse nanoparticles generated by the evaporation and condensation method were made into bipolar charge in the Boltzmann distribution using polonium (210-polonium). Next, spherical silver nanoparticles having a diameter of 20 nm were extracted by adjusting the center electrode voltage of the differential mobility analyzer (DMA) to -810 V (geometric standard deviation: 1.167). The nanoparticles were used as test aerosols. This nanoparticle classification and deposition process is schematically illustrated in FIG. 1.

The monodisperse nanoparticles extracted above were deposited by connecting to an electro-static precipitator (ESP). That is, after spin-coating a photosensitive film on the cleaned deposition substrate, a desired pattern was formed through a photolithography process. After depositing the charged monodisperse nanoparticles extracted therein, the photoresist was removed using acetone and ultrapure water, and a pattern assembly of nanoparticles was obtained by cleaning and drying. The deposition process of such nanoparticles is schematically illustrated in FIG. 2.

In this embodiment, monodisperse nanoparticles were deposited at the ESP center electrode voltage of -4.5 kV in consideration of deposition efficiency and dendritic aggregate formation problem, and the structure of the electrostatic deposition apparatus is described in more detail with reference to FIG. 3. Is shown.

FIG. 4 is a SEM photograph of a micrometer linewidth pattern structure implemented with 20 nm diameter silver nanoparticles obtained in Example 1, and FIG. 5 is a high magnification photograph of a specific block of FIG. 4.

6 is a SEM photograph of a nanometer linewidth pattern structure having a width of 100 nm, which is implemented with the 20 nm diameter silver nanoparticles obtained in Example 1, and FIG. 7 shows nanoparticle structures having a 800 nm to 100 nm linewidth. Non-contact SPM scanning picture.

As can be seen in Figures 4 to 7 the nano-patterning method of the present invention reduces the number of noise particles deposited outside the pattern to the ultimate level, productivity and reproducibility is also significantly higher than other techniques. In addition, in the manufacture of soft masks, portability that can be applied to conventional photolithography, electron-beam direct writing, nano-imprint lithography, and soft lithography. And scalability.

Therefore, when fabricating a structure assembled with nanoparticles by the nanoparticle patterning technology of the present invention, it is possible to manufacture a gas sensor having a much higher reactivity than the conventional gas sensor, nanotubes and nanoparticles in the pattern deposition of metal nanoparticles It becomes a catalyst particle of wire growth and can be applied to growth position control.

<Example 2>

The photoresist of the silver nanoparticles having a diameter of 20 nm obtained in Example 1 was removed, and the sintered nanostructures were obtained by heat-treating 500 nm dots formed therefrom at 400 ° C. for 120 minutes in a tube heat treatment process.

FIG. 8 is an SEM photograph of the dot-shaped sintered compact obtained in Example 2, and FIG. 9 is a scanning photograph in the SPM non-contact mode of the sintered compact shown in FIG. 8.

The method for producing a nanoparticle pattern structure according to the present invention reduces the number of noise particles deposited outside the pattern to an ultimate level, and is excellent in productivity and reproducibility, and portability and expandability to other technologies. Therefore, according to the present invention, the nano-size pattern structure can be manufactured with high efficiency and high purity, and the sintered body manufacturing method of the nanoparticle pattern according to the present invention has an effect of reducing the line width and has an economical and time advantage.

Claims (6)

 a) making the polydisperse nanoparticles into a bipolar charge state; b) introducing charged nanoparticles into a differential mobility analyzer (DMA) and adjusting the central electrode of the DMA to extract monodisperse nanoparticles of a desired size; c) placing the deposition substrate on which the desired photoresist pattern is formed on the center electrode of the electrostatic deposition apparatus, and applying a voltage to the center electrode; d) injecting the charged monodisperse nanoparticles obtained in step b) into the electrostatic deposition apparatus and inducing deposition on the substrate by an electric field generated between the voltage of the center electrode and the grounded voltage of the outer cylinder; And e) removing the photoresist pattern on the substrate. The method of claim 1, Nanoparticle patterning method characterized in that for producing the monodisperse nanoparticles by evaporation and condensation method. The method of claim 1, Nanoparticle patterning method characterized in that the polydispersion nanoparticles to make a bipolar charge state to the Boltzmann distribution using polonium (210-polonium). The method of claim 1, The method of nanoparticle patterning, characterized in that the magnitude of the voltage applied to the center electrode of the electrostatic deposition apparatus is selected in the range of -10 to +10 kV. The nanoparticle sintered body manufacturing method comprising the heat treatment and sintering the nanoparticle pattern produced by the method of claim 1. The method of claim 5, wherein A method for producing a nanoparticle sintered body, wherein the nanoparticle pattern is sintered in a heat treatment step into a tube.

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