KR102164381B1 - Method for manufacturing nanostructure and nanostructure manufactured by using the same - Google Patents

Abstract

A method of manufacturing a nanostructure and a nanostructure manufactured using the same are disclosed. In the present invention, a metal mask is patterned according to a preset pattern on an upper portion of a substrate to overcome the limitation of resolution of photolithography, and the intensity of an electric field generated around the patterned metal mask on the substrate is relatively Nanostructures smaller than the size of the metal mask can be manufactured by dry etching the surface of the substrate exposed to the outside in addition to the surface on which the metal mask is patterned among the surfaces of the substrate using a high local electric field.

Description

A method of manufacturing a nano structure, and a nano structure manufactured using the same TECHNICAL FIELD [METHOD FOR MANUFACTURING NANOSTRUCTURE AND NANOSTRUCTURE MANUFACTURED BY USING THE SAME}

The present invention relates to a method of manufacturing a nanostructure by finely controlling a dry etching process, and to a nanostructure manufactured using the same.

The content described in this section merely provides background information on the present embodiment and does not constitute the prior art.

In a general lithography method, a polymer material (e.g., photoresist, etc.) having reactivity to light is applied on a substrate on which a material to be patterned is laminated (or deposited), and is designed in an arbitrary pattern. A pattern mask (or etching mask) having a target pattern is formed on the material to be patterned by exposing it by transmitting light onto the polymer material through a reticle and removing the exposed polymer material through a development process. This is a method of patterning a material stacked on a substrate into a desired pattern by performing an etching process using the.

However, in the photolithography method described above, the resolution, which is one of the key factors in the development of lithography technology for producing microstructures, depends on the numerical aperture (NA) of the lens and the wavelength of light used in lithography. For this, a lens having a short wavelength of light and a large numerical aperture is required, but conventionally, there is a problem in that it is difficult to fabricate a structure smaller than the wavelength of light.

The dry etching method is an etching method capable of freely forming an anisotropic fine pattern with a large aspect ratio (AR) with a small amount of gas. However, since it is difficult to finely control the above-described etching process, undercutting, which is a phenomenon in which the material at the bottom of the mask is etched, profile tilting, which indicates inclination of the etching profile, and the lower portion of the gate electrode are in the lateral direction. Notching, bowing effect, which is a phenomenon that is etched abnormally, loading effect, or charging, which is a phenomenon in which the etching rate is decreased due to insufficient etchant or etching gas that reacts with the substrate. There is a problem that unwanted side effects such as a charging effect occur.

The present invention utilizes the Bowing effect, which is one of the side effects of the dry etching process, to pattern a metal mask on a substrate so as to exceed the limit of resolution of photolithography, and to form a relative layer around the patterned metal mask. To provide a method of manufacturing a nanostructure having a sub wavelength structure of less than the visible light wavelength by etching a substrate by changing the etching trajectory of the active etching ions by controlling a high electric field, and a nanostructure manufactured using the same. have.

A method of manufacturing a nanostructure according to an embodiment of the present invention for achieving the above object includes: patterning a metal mask on a substrate according to a preset pattern; And dry-etching the surface of the substrate exposed to the outside in addition to the surface on which the metal mask is patterned among the surfaces of the substrate, wherein the dry etching of the surface of the substrate is performed when the dry etching is performed. The surface of the substrate exposed to the outside may be dry-etched by using a local electric field in which the intensity of an electric field generated around the patterned metal mask is relatively high in a portion of the patterned metal mask.

Preferably, in the dry etching of the surface of the substrate, the surface of the substrate may be dry etched by adjusting the trajectory of active etching ions, which are ions that are etched by reacting with the substrate using the formed local electric field.

Preferably, in the dry etching step, the local electric field is changed by adjusting the thickness of the metal mask, so that the angle at which the trajectory of the active etching ions is bent may be adjusted.

Preferably, the metal mask may have a thickness in the range of 40 nm to 100 nmn.

Preferably, in the dry etching step, when the amount of the active etching ions reaching the metal mask and the substrate is saturated, the saturated active etching ions are deflected according to the diameter of the metal mask having a preset thickness. The surface of the substrate may be dry etched by changing the lateral etching degree, which represents the degree to which the side surfaces of the substrate are etched.

Preferably, in the dry etching step, the pitch of the metal mask pattern may be adjusted to adjust the angle at which the trajectory of the active etching ions is bent.

Preferably, in the dry etching step, as the dry etching time increases, the lateral etching degree of the substrate decreases and the vertical etching degree of the substrate increases. By controlling the degree of side etching, the surface of the substrate may be dry etched.

Preferably, the step of patterning the metal mask includes applying a photoresist layer on the substrate; Forming a photoresist pattern by developing a photoresist layer applied on the substrate into the preset pattern; And depositing the metal mask according to the formed photoresist pattern; wherein the local electric field is formed near an edge or sidewall of the patterned metal mask, and the dry etching is performed by reactive ion etching. Ion Etching, RIE).

In addition, the present invention includes a nanostructure manufactured by the method for manufacturing the nanostructure described above.

According to the embodiment of the present invention as described above, it is possible to overcome the resolution limitation of photolithography, electron beam lithography, or X-ray based lithography.

In addition, according to an embodiment of the present invention, it is possible to increase the degree of freedom of patterning beyond the limit of lithography by proposing optimized parameters for controlling the size of the nanostructure by changing the type and structure of a metal mask that can change the size of the electric field. It has the advantage of being able to reduce the cost of the process while still being.

In addition, according to an embodiment of the present invention, not only manufacturing of silicon nanostructures for contact transfer printing and imprinting, but also of anti-reflection structures and solar cells using tapered sidewalls. It can be applied to light trapping, and has the advantage of being able to be used as an LED, a photodetector, or a photoimager.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a flowchart illustrating a method of manufacturing a nanostructure according to an embodiment of the present invention.
FIG. 2 is a view for explaining a state of a substrate on which a metal mask is patterned and a state of a nanostructure manufactured by etching the substrate on which the metal mask is patterned according to an embodiment of the present invention.
3 is a flowchart illustrating a detailed method of patterning a metal mask according to an embodiment of the present invention.
4 is a view for explaining a specific method of patterning a metal mask on a substrate according to an embodiment of the present invention.
5 is a view for explaining a specific method of manufacturing a nanostructure using an ICP-RIE process and a distribution diagram of a local electric field formed around a metal mask according to an embodiment of the present invention.
6 is a diagram for explaining distribution of a local electric field around a metal mask according to the thickness of the metal mask.
7 is a view for explaining a method of adjusting a bending angle of an orbit of an active etching ion by adjusting a thickness of a metal mask according to an embodiment of the present invention.
8 is a view for explaining a method of manufacturing a nanostructure by changing the thickness of a metal mask according to an embodiment of the present invention.
9 is a diagram illustrating a degree of lateral etching of a substrate measured while changing a diameter of a metal mask having a preset thickness in order to manufacture a nanostructure according to an embodiment of the present invention.
10 is a diagram illustrating the diameter of a nanostructure formed by etching according to a pitch of a metal mask according to an embodiment of the present invention.
11 illustrates a change in a lateral etching rate of a substrate according to an etching process time when a process of etching a substrate patterned with a metal mask according to an embodiment of the present invention is performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments to be posted below, but may be implemented in a variety of different forms, and only these embodiments make the posting of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

In the present specification, terms such as "first" and "second" are used to distinguish one component from other components, and the scope of the rights is not limited by these terms. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

In the present specification, the identification code (eg, a, b, c, etc.) is used for convenience of description, and the identification code does not describe the order of each step, and each step is clearly in context. It may occur differently from the specified order unless a specific order is specified. That is, each of the steps may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

In this specification, expressions such as “have”, “may have”, “include” or “may include” indicate the existence of a corresponding feature (eg, a number, function, operation, or component such as a part). Points, and does not exclude the presence of additional features.

1 is a flowchart illustrating a method of manufacturing a nanostructure according to an embodiment of the present invention.

A metal mask is patterned on the substrate according to a preset pattern (S110).

The method of manufacturing a nanostructure according to an embodiment of the present invention is a method capable of directly manufacturing a nanostructure on a substrate corresponding to a target, and may directly manufacture a nanostructure on the substrate corresponding to the target.

The above-described substrate may include any one or two or more selected from the group consisting of silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium gallium arsenide (InGaAs), and preferably a wafer including Si Can be More preferably, the Si may be crystalline Si, and the crystalline Si may be monocrystalline silicon, polycrystalline silicon, and a combination thereof.

According to an embodiment of the present invention, a patterned etching mask may be created on the substrate by patterning an etching mask having a metallic property on the substrate, and the etching mask having the above-described metallic property is free to represent a carrier carrying electric charges. It may be a metal mask containing gold (Au) belonging to the 6th period of Group 11 of the periodic table having many free carriers.

In the following specification, for convenience of description, an etching mask having metallic properties is defined as a metal mask. However, the above-described example is only an example for explaining an embodiment of the present invention, and is not limited thereto.

Among the surfaces of the substrate, the surface of the substrate exposed to the outside in addition to the surface on which the metal mask is generated is dry-etched (S120).

The etching gas used for dry etching according to an embodiment of the present invention may be any one or a mixture of two or more gases selected from the group consisting of CF ₄ , CHF ₃ , SF ₆ , Ar, Cl ₂ and O ₂ .

According to an embodiment of the present invention, it is possible to adjust the size of the nanostructure formed on the substrate with only one type of metal mask.

When dry etching the surface of the substrate according to an embodiment of the present invention, the intensity of the electric field generated around the metal mask patterned on the substrate is relatively high in some portions of the metal mask patterned on the substrate. A local electric field can be formed.

Therefore, when dry etching the surface of the substrate according to an embodiment of the present invention, the surface of the substrate is exposed to the outside except for a portion covered by the patterned metal mask using a local electric field formed by a metal mask patterned on the substrate. The surface of the substrate can be dry etched.

Accordingly, in the method of manufacturing a nanostructure according to an embodiment of the present invention, a nanostructure may be manufactured using a local electric field formed around a metal mask that may occur during a dry etching process.

The dry etching according to the embodiment of the present invention described above may be reactive ion etching (RIE).

The above-described reactive ion etching (RIE) process uses a method of etching silicon with plasma.

Plasma represents a gaseous state separated into negatively charged electrons and positively charged ions at ultra-high temperature, and at this time, it has a property of being neutral because the charge separation is quite high and the number of negative and positive charges is the same overall.

In plasma etching, an etching gas containing fluorine, chlorine, oxygen, or the like is activated by a high-frequency electric field to generate plasma.

Plasma contains active species such as charged particles (hereinafter referred to as “ions”) and neutral particles (hereinafter referred to as “radicals”). Active species such as ions or radicals react with the surface of the substrate to generate a reaction product, and etching may proceed by volatilization of the resulting reaction product. For example, radicals arriving at the substrate directly react with atoms constituting the substrate, become volatile gases, and are gradually departed from the surface, so that etching occurs as the surface of the substrate is gradually cut off.

Therefore, in the reactive ion etching (RIE) according to an embodiment of the present invention, when the above-described etching occurs and the ions in the plasma are accelerated and irradiated to the substrate, the visual reaction of the surface where the ions collide is promoted, thereby directional etching. Show.

In addition, an inductively coupled plasma reactive ion etching (ICP-RIE) process may be used as a method of dry etching a substrate to fabricate a nanostructure according to an embodiment of the present invention. The above-described ICP-RIE process will be described later in FIG. 4.

Specifically, in the method of manufacturing a nanostructure according to an embodiment of the present invention, the deflection of the active etching ions can be adjusted using a local electric field generated by the patterned metal mask, and accordingly, the size of the nanostructure is adjusted to Can be manufactured. That is, a nanostructure can be manufactured by etching the side of the substrate using the trajectory of the active etching ions adjusted according to the local electric field formed around the patterned metal mask on the substrate.

Accordingly, the method of manufacturing a nanostructure by controlling a local electric field formed by a metal mask according to an embodiment of the present invention is not inducing an electrostatic force, but rather an activity that is directly affected by the above-described local electric field itself. By controlling the trajectories of the etching ions, the degree of etching of the sidewalls of the substrate can be controlled to manufacture a nanostructure whose size is further reduced by one step.

The change in the trajectory of the active etching ions corresponding to the ions that chemically reacts while colliding with the surface of the substrate to etch the portion of the collided substrate can be explained by the Boeing effect induced by the change in the local electric field formed around the metal mask.

Mainly, the Boeing effect can be caused by a mask's side slope effect and a non-efficient protection layer, but in general, the Boeing effect is mainly due to a charge effect or notching. This is described when using an insulator-type mask that also shows formation, and the above-described bowing effect may be caused by the surrounding environment that appears due to the metal-based mask.

In the method of manufacturing a nanostructure according to an exemplary embodiment of the present invention, the substrate may be etched using a bowing effect caused by the surrounding environment caused by the above-described metal-based mask.

As a method of manufacturing a nanostructure by changing the trajectory of the above-described active etching ions, a method of adjusting the magnitude of the local electric field formed around the above-described metal mask may be used.

Specifically, it is possible to change the etching trajectory of the active etching ion species used in the non-Bosch process by adjusting the size of the local electric field formed around the metal mask according to an embodiment of the present invention. The magnitude of the local electric field formed at this time is expressed as ΔE.

The Bosch process is a process of alternately performing dry etching using inductively coupled plasma (ICP), which is a high-density plasma, and a process of depositing a polymer layer on the surface (polymerization). In the case of etching, the etching to the side is delayed as much as possible. Accordingly, the above-described Bosch process can perform relatively larger anisotropic etching than other etching methods, and as a result, can generate deep holes.

When a deep reactive ion etching (DRIE) process is performed by the Bosch process described above, two steps may be repeatedly performed to obtain a vertical structure.

The first step represents etching based on SF ₆ (Sulfur hexafluoride) gas capable of isotropic plasma etching, and the second step is a chemically stable passivation layer. A process capable of depositing is in progress, which can form a protective film on which Teflon is deposited using mainly C ₄ F ₈ (Octafluorocyclobutane) gas.

In the above-described deep reactive ion etching (DRIE) process, etching and protective film processes are essential.

The two steps described above are a method that can maximize the advantages of the DRIE process, but the two steps described above can form an undulate shape of hundreds of nanometers (100-500 nm) on the sidewall. It has a drawback.

Unlike the Bosch process, which is divided into the above two steps, the Non-Bosch process is a method of simultaneously performing etching and polymer deposition, and the non-Bosch process is a CF ₄ or C ₄ F, which is a CF _x series gas. Evaporation and etching can be performed by using ₈ gas and SF ₆ , which is a SF _x- based gas, at the same time.

In the case of performing a non-Bosch process or a nonswitching peudo-Bosch process instead of the above-described Bosch process, since there is no protective film, an anisotropic etching profile (EP) is not formed. An isotropic etching profile (EP) can be obtained, or a structure with a severely inclined sidewall can be obtained.

The etching profile EP described above may refer to a set of arbitrary values for a set of one or more geometric coordinates that may be used to characterize the shape of an etched feature on a semiconductor substrate. In the simple case, the etch profile can be approximated to the width of the feature determined halfway to the base of the feature when viewed through a two-dimensional vertical section slice through the feature. The intermediate to the base of the feature described above represents an intermediate point between the base or lower end of the feature on the surface of the substrate and the upper opening of the feature. In a more complex example, the etch profile (EP) can be a series of feature widths determined at various heights above the base of the feature when viewed through the same two-dimensional vertical section slice.

The point of obtaining an isotropic etching profile (EP) or a structure with a severely inclined sidewall is mainly disadvantages obtained during a process other than the Bosch process, but the nanostructure manufacturing method according to an embodiment of the present invention Using the above-described disadvantages, the degree to which the side of the substrate is etched can be controlled, and a nanostructure that is much smaller than the size of a metal mask corresponding to the etching mask can be generated.

As the magnitude (ΔE) of the local electric field formed according to an exemplary embodiment of the present invention increases, the bending angle of the active etching ion trajectory also increases.

Accordingly, since the bending angle of the active etching ion orbit is adjusted by adjusting the size of the local electric field described above, nanostructures of various sizes according to an embodiment of the present invention can be manufactured according to the bending angle of the active etching ion orbit.

Specifically, as the angle at which the trajectory of the active etching ions is bent increases, the degree of undercutting increases because the active etching ions enter directly under the metal mask to etch the substrate. Accordingly, nanoparticles having a size smaller than the size of the metal mask The structure can be manufactured.

Therefore, in the related art, the structure can be manufactured only at the point where the energy is stabilized. Unlike this, in the case of using the nanostructure manufacturing method according to an embodiment of the present invention, the nanostructure can be manufactured on all the substrates capable of nano etching.

In addition, when the nanostructure is manufactured by the above-described method, sidewall etching is used even under conditions where active ionic species, amount of active species, bias power, and pressure are constant among dry plasma etching conditions. Thus, the size of the nanostructure can be adjusted.

In addition, in order to manufacture a nanostructure according to another embodiment of the present invention, the type of gas, gas mixture ratio, pressure, and bias power are controlled by controlling the degree of lateral etching of the substrate. Alternatively, the degree of lateral etching of the substrate may be adjusted according to the degree of formation of sidewall passivation.

In addition, the nanostructure manufacturing method according to an embodiment of the present invention may manufacture a nanostructure by etching a substrate on which a metal mask is patterned according to a thickness, a diameter of a metal mask, a pitch of a metal mask pattern, or an etching time. The parameters or etching time of the metal mask described above will be described with reference to FIG. 2.

FIG. 2 is a view for explaining a state of a substrate on which a metal mask is patterned and a state of a nanostructure manufactured by etching the substrate on which the metal mask is patterned according to an embodiment of the present invention.

FIG. 2(a) is a view for explaining a state of the substrate 100 on which the metal mask 200 is patterned according to an embodiment of the present invention. Referring to FIG. 2(a), an embodiment of the present invention According to the method of manufacturing a nanostructure, while controlling the thickness 210 of the metal mask 200, the diameter 220 of the metal mask 200, the pitch 230 of the metal mask 200, or the etching time 240 A nanostructure may be manufactured by etching the substrate 100 on which the mask 200 is patterned.

FIG. 2(b) is a view for explaining the appearance of a nanostructure manufactured by etching the substrate 100 on which the metal mask 200 is patterned according to an embodiment of the present invention. Referring to FIG. 2(b) , The diameter (r') of the etched substrate 100 corresponding to the nanostructure manufactured according to an embodiment of the present invention is the degree of lateral etching of the substrate 100 at the diameter 220 of the metal mask 200 (Δr ') is etched.

In addition, when the substrate 100 is etched using a dry etching process, since it may be etched in a vertical direction as well as in the lateral direction, the depth h of the etched substrate 100 is etched in the vertical direction. Indicates the degree.

3 is a flowchart illustrating a detailed method of patterning a metal mask according to an embodiment of the present invention.

A photoresist layer is applied on the substrate (S111).

The above-described substrate represents an appropriate substrate commonly used in processes involving photoresists, and the above-described photoresist may be a photoresist commonly used in the semiconductor industry, and may be photoresists of 193 nm and 248 nm. It is not limited. Preferably, as the photoresist described above, chemically amplified photoresist, positive-tone photoresists, or negative-tone photoresists may be used. have.

In the positive-type photoresist layer, the light-exposed region is etched and removed in a subsequent development process. Conversely, the negative-type photoresist layer has a characteristic that the remaining regions excluding the exposed region are etched. Hereinafter, a case in which a photoresist layer is formed in a negative type and an unexposed area is etched is described as an example, but the present invention is not limited thereto, and the exposed area is etched using a positive type photoresist layer to be described later. A metal mask can be patterned on the substrate.

The above-described photoresist layer can be applied by standard means generally common in nature, and can be applied by standard means including, for example, spin coating.

The above-described photoresist layer may be baked to remove residual solvent from the photoresist and improve coherence of the photoresist layer.

A photoresist pattern is formed by developing the photoresist layer applied on the substrate in a preset pattern (S112).

According to an embodiment of the present invention, light is irradiated to the photoresist layer applied on the substrate, but by disposing a light source emitting light and a mask having a preset shape to irradiate light to the photoresist layer, A preset pattern can be formed.

According to an embodiment of the present invention, a photoresist pattern is formed on a substrate by irradiating light to form a preset pattern on the photoresist layer, developing exposed areas, and etching only the unexposed areas except for the exposed areas. can do.

Specifically, when a photoresist layer on which a pattern is formed in advance by the exposed areas is put into a developer based on a KOH solution, the lighted portion remains and the non-lighted portion melts away and the photoresist on the substrate. A resist pattern can be formed.

A metal mask is deposited according to the photoresist pattern formed on the substrate (S113).

Specifically, a metal mask having a preset pattern may be patterned on the substrate by depositing a metal mask according to the photoresist pattern formed on the substrate and removing the photoresist layer according to an embodiment of the present invention.

For example, according to an embodiment of the present invention, after depositing gold (Au) using a metal evaporator such as an evaporator or sputter in the area where the photoresist layer is etched, the above-described photoresist layer is deposited. When removed, a metal mask array having a preset pattern can be patterned on the substrate.

A detailed method of patterning the above-described metal mask will be described with reference to FIG. 4.

4 is a view for explaining a specific method of patterning a metal mask on a substrate according to an embodiment of the present invention.

Referring to FIG. 4, in order to manufacture a nanostructure according to an embodiment of the present invention, a process of first patterning an etching mask having metallic properties on a substrate may be performed.

Referring to FIG. 4(a), a photoresist layer 310 is applied on a substrate 100 according to an embodiment of the present invention, and UV light emitted from the UV light source 320 corresponds to a preset shape. The mask 330 is irradiated, and the shape of the irradiated mask 330 is irradiated to the photoresist layer 310 applied on the substrate 100 by focusing UV light using the lens 340, A pattern set in advance in 310 may be generated.

Preferably, the wavelength of the above-described UV light source 320 may be 405 nm, but the above-described example is only an example for describing an embodiment of the present invention and is not limited thereto.

The mask 330 corresponding to the above-described preset shape corresponds to an equipment in which hundreds of thousands of micro-mirrors are integrated into a semiconductor chip using MEMS (Micro Electro Mechanical System) technology, and is a device that changes the optical path of light. It may be a Digital Micromirror Device (DMD) dynamic mask, and the photoresist layer can be directly exposed without a photo mask.

The lens 340 described above may be an objective lens, but is not limited thereto.

The thickness of the metal mask 200, the diameter of the metal mask 200, and the pitch of the metal mask 200 pattern may be determined by the above-described preset pattern. The above-described preset pattern may be a micro pattern having a micrometer size, but is not limited thereto.

Referring to FIG. 4B, a photoresist layer 310 having a preset pattern generated in FIG. 4A may be developed using a solution.

Of the above-described photoresist layer 310, the portion 311 not exposed to UV light will be dissolved in the photoresist developer, and the portion of the photoresist layer 310 exposed to UV light will be non-dissolved in the photoresist developer.

Accordingly, the photoresist layer 310 can be developed by dissolving only the portion 311 of the photoresist layer 310 corresponding to a predetermined pattern in the photoresist layer 310 not exposed to UV light in a developer solution.

Referring to FIG. 4C, gold (or Au) 200 may be deposited on the photoresist layer 310 developed in FIG. 4B and the photoresist layer 310 may be removed.

Accordingly, the metal mask 200 having a preset pattern is deposited on the substrate 100 by depositing the metal mask 200 on the substrate 100 using the method shown in FIGS. 4A to 4C. It can be patterned on.

Accordingly, the above-described etching target material, the substrate 100, is in a state in which the metal mask 200 corresponding to the etching mask 200 is patterned so that a portion to be etched and a portion to be etched are partitioned.

Accordingly, in the method of manufacturing a nanostructure according to an embodiment of the present invention, a nano-sized structure may be manufactured by etching a portion of the substrate 100 located under the etching mask 200 having micro-sized metallic properties.

5 is a view for explaining a specific method of manufacturing a nanostructure using an ICP-RIE process and a distribution diagram of a local electric field formed around a metal mask according to an embodiment of the present invention.

Referring to FIG. 5A, according to an embodiment of the present invention, a nanostructure may be manufactured on a substrate patterned with a metal mask using an ICP-RIE process. Specifically, the substrate 100 on which the metal mask 200 is patterned may be etched by forming a plasma 410 to contain active etching ions formed in the ICP-RIE process.

The substrate 100 on which the metal mask 200 is patterned according to an embodiment of the present invention may be located in the vacuum chamber 420. The vacuum chamber 420 described above is isolated from the environment from the outside by using a vacuum pump 480 to achieve a vacuum state.

The gas injection unit 430 according to an embodiment of the present invention can provide a reactive gas including a gas such as SF6, CF4, or CF6 into the vacuum chamber 420, so that the gas injection unit 430 provides The reaction gas may be filled in the vacuum chamber 420.

The substrate 100 patterned with the metal mask 200 may be mounted on the holder 440 supporting the substrate 100 as an etching target material by the ICP-RIE process according to an embodiment of the present invention.

The RF generator 460 may apply a high frequency to the reaction gas filled in the vacuum chamber 420. Specifically, the helical coil 450 installed on the upper or side of the vacuum chamber 420 and the RF matching network 470 connected to the holder 440, and the helical coil 450 and the RF matching network 470 are connected to 13.56 An RF generator 460 that generates an RF frequency of MHZ, generates an inductive inductance component in the plasma 410 by applying RF power, and a magnetic field (B-Field) from the current flowing through the spiral coil 450 This can be induced, the induced magnetic field B can be formed in a vertical direction, and the electric field (E-Field) can be formed in parallel (∇XE≠0).

Therefore, it is possible to form a high-density plasma 410 by rotating electrons along the magnetic field B in the vertical direction and the electric field E in the horizontal direction and colliding with gas particles, and active etching constituting the formed plasma 410 The substrate 100, which is an etching target material supported on the holder 440, may be etched using ions, thereby manufacturing a nanostructure.

According to an embodiment of the present invention, after etching the substrate 100 as an etching target material by the above-described method, the metal mask 200 used for etching is removed using a gold etchant. ) Can be removed to prepare a nanostructure.

Referring to FIG. 5(b) together, the E-field distribution around the metal mask 200 patterned by the above-described method appears larger than at other locations, and in particular, the edge portion of the metal mask 200 At, the local electric field 500 in which the electric field is concentrated can be confirmed, and it can be seen that the strength of the electric field is relatively large even in the vicinity of the sidewall of the metal mask 200.

Accordingly, it can be seen that the change in the trajectory of the active etching ions is affected by the edge and side of the metal mask rather than the top of the metal mask.

6 is a diagram for explaining distribution of a local electric field around a metal mask according to the thickness of the metal mask.

6, as the thickness (l) of the metal mask 200 patterned on the substrate 100 increases, the distribution of the local electric field (V/m) around the edge of the metal mask 200 (d) increases. I can confirm that.

7 is a view for explaining a method of adjusting a bending angle of an orbit of an active etching ion by adjusting a thickness of a metal mask according to an embodiment of the present invention.

Referring to FIG. 7, when adjusting the thickness of the metal mask 200 according to an embodiment of the present invention, the magnitude of the local electric field (ΔE) and the effective range (d/l) that the local electric field affects the etching of the substrate 100 ) Can also be adjusted. Referring to FIG. 6 together, l denotes the thickness of the metal mask, and d denotes a distribution diagram of a local electric field formed by the metal mask.

Specifically, according to an embodiment of the present invention, as the thickness of the metal mask 200 increases, the size of the local electric field formed around the metal mask 200 increases, and accordingly, the trajectory of the active etching ions 411 The bend angle can also be increased.

However, there is a range in which side etching of the substrate is effectively performed based on the Boeing effect, and can be classified into three regions, a first region to a third region.

Referring to FIG. 7(a), since the size of the local electric field and the thickness of the metal mask are not thick in the first region, the amount of deflection of the active ionic species is small, and the trajectory of the active etching ions 411 is at a first angle. The substrate can be etched by being changed by (θ ₁ ), and on the right side of FIG. 7(a), the trajectory of the active etching ions 411 is changed by a first angle (θ ₁ ), thereby forming a nanostructure manufactured by etching the substrate. It is shown as an image of a scanning electron microscope (SEM). In addition, since the thickness of the metal mask is not thick, it cannot play a role as a general metal mask. Accordingly, in the case of manufacturing a structure by etching the substrate by adjusting the thickness of the metal mask within the range included in the first region, it is difficult to manufacture while adjusting the size of the structure.

On the other hand, referring to FIG. 7(b), in the second region, the size of the local electric field increases in proportion to the thickness of the metal mask 200, and the effective range (d/l) that the local electric field has on etching the substrate 100 ) Also increases. Accordingly, the bending angle of the trajectory of the active etching ions 411 is also increased, so that the trajectory of the active etching ions 411 is changed by the second angle θ ₂ , so that the substrate can be etched, and the right side of FIG. 7(b) A nanostructure manufactured by etching a substrate by changing the trajectory of the active etching ions 411 by a second angle θ _{2 is} shown as an image of a scanning electron microscope (SEM). As the angle at which the above-described active etching ions 411 are deflected increases, the degree of undercutting by which the substrate 100 immediately under the metal mask 200 is etched also gradually increases. Accordingly, when the thickness of the metal mask is adjusted within the range of the second region, a nanostructure having a size smaller than that of the metal mask may be manufactured.

Referring to FIG. 7(c), in the third region, the local electric field has the largest magnitude and the thickness of the metal mask is also the thickest region. The deflection of) is also greatly increased, so that the trajectory of the active etching ions 411 is changed by a third angle θ ₃ . However, when the thickness of the metal mask is adjusted within the range of the third area, the thickness of the metal mask is thicker than that of the first area and the second area, so that a large amount of bent active etching ions 411 interact with the metal mask to effectively undermine. It is impossible to cut, and the trajectory of the active etching ions 411 shown on the right side of FIG. 7(c) is changed by a third angle (θ ₃ ), and the scanning electron microscope (SEM) of the nanostructure manufactured by etching the substrate You can also check it from the image.

Therefore, when the thickness of the metal mask 200 is adjusted within the second region as shown in FIG. 7(b), when the substrate 100 is etched using the electric field and the thickness change of the metal mask 200, the bowing effect is reduced. You can obtain the desired nanostructure while maximizing.

The first to third areas described above will be described in detail in FIG. 8.

8 is a view for explaining a method of manufacturing a nanostructure by changing the thickness of a metal mask according to an embodiment of the present invention.

8(a) is a graph showing a change in a diameter of an etched substrate according to a thickness of a metal mask according to an embodiment of the present invention.

Referring to FIG. 8(a), the first region represents a region in which the thickness of the metal mask is between 5 nm and 30 nm, the second region represents the region in which the thickness of the metal mask is between 40 nm and 100 nm, Area 3 represents an area in which the thickness of the metal mask is greater than 100 nm.

Specifically, the mark displayed in the first area represents the diameter of the etched substrate in the range of about 5 nm to 30 nm in the thickness of the metal mask, and the mark displayed in the second area indicates the thickness of the metal mask in the range of about 40 to 100 nm. The diameter of the etched substrate is indicated in the range of, and the mark indicated in the third area indicates the diameter of the substrate etched at 150 nm in thickness of the metal mask.

8(b) to 8(j) show SEM images of each of the etched substrates according to the thickness of the metal mask marked in FIG. 8(a) output by a scanning electron microscope (SEM). .

Specifically, the thickness of the metal mask in Fig. 8(b) is 5 nm, in Fig. 8(c) it is 10 nm, in Fig. 8(d) it is 20 nm, in Fig. 8(e) it is 30 nm, and in Fig. 8(f) In Fig. 8(g), it is 40 nm, in Fig. 8(h) it is 70 nm, in Fig. 8(i) it is 100 nm, in Fig. 8(j) it is 150 nm, and Figs. 8(b) to 8 All of the etching times in (j) indicate that they are 125 (s) the same.

8(b) to 8(f) show a tendency that the diameter of the substrate increases with the diameter of the etched substrate according to the thickness of the metal mask included in the first region, but FIGS. 8(f) to 8(i) Up to ), it can be seen that even if the thickness of the metal mask increases from 40 nm to 100 nm according to the thickness of the metal mask included in the second region, the diameter of the etched substrate decreases.

FIG. 8(j) shows the diameter of the substrate etched at 150 nm, which is the thickness of the metal mask included in the third area. Compared to FIG. 8(i), the thickness of the metal mask is increased, and the diameter of the etched substrate is also shown in FIG. It can be seen that it has increased compared to (i).

9 is a diagram illustrating a degree of lateral etching of a substrate measured while changing a diameter of a metal mask having a preset thickness in order to manufacture a nanostructure according to an embodiment of the present invention.

Referring to FIG. 9(a), when it is assumed that the amount of active etching ions reaching the metal mask and the substrate is saturated and the amount of active etching ions reaching the metal mask and the substrate is uniform, one of the present inventions It can be seen that as the diameter of the metal mask having the preset thickness l according to the embodiment increases, the Δdiameter indicating the degree of lateral etching of the substrate also increases. That is, it can be seen that as the diameter of the metal mask increases, the deflection of the above-described uniform active etching ions increases, thereby further generating the bowing effect.

Conventionally, even when the diameter of the metal mask was increased by the above-described method, the degree of side etching of the substrate was the same and constant undercutting occurred.

As the diameter of the metal mask according to an embodiment of the present invention increases, the arc length of electric field also increases, and the thickness (l) of the metal mask is a side of the diameter of the metal mask in which the electric field is formed. The arc length of the electric field in the direction corresponding to (lateral) may also be included.

Accordingly, the size of the local electric field formed by the metal mask can be controlled according to the diameter of the metal mask described above according to an embodiment of the present invention, and accordingly, the degree of lateral etching of the substrate is etched. The nanostructure can be manufactured by adjusting according to the diameter of the metal mask corresponding to the mask.

FIG. 9(b) shows an SEM image of each etched substrate according to the diameter of a metal mask having a thickness of 50 nm marked in FIG. 9(a), output by a scanning electron microscope (SEM).

Referring to FIG. 9(b), when the diameter of the metal mask having a thickness of 50 nm marked in FIG. 9(a) increases to 1 nm, 2 nm, 3 nm, and 4 nm from the left, indicating the degree of side etching of the substrate. It shows the experimental result of increasing Δr'(ΔDiameter).

10 is a diagram illustrating the diameter of a nanostructure formed by etching according to a pitch of a metal mask according to an embodiment of the present invention.

Referring to FIG. 10(a), the method of manufacturing a nanostructure according to an embodiment of the present invention is a nanostructure by controlling the degree to which a substrate is etched according to a pitch of a metal mask pattern indicating a gap between metal masks. Can be manufactured.

Specifically, referring to FIG. 10(a), when the pitch of the metal mask pattern according to an embodiment of the present invention is micro-sized, even if the pitch of the metal mask pattern changes, the diameter of the nanostructure formed by etching the substrate is large. You can see that there is no change.

Therefore, when the pitch of the metal mask pattern is micro-sized, even if the pitch of the metal mask pattern changes, it can be confirmed that there is no significant change in the size control of the nanostructure by undercutting, and at the same time, the nanostructure can be stably formed. have.

Referring to the left drawing of FIG. 10(b), the amount of active etching ions constituting the plasma 410 reaching the metal mask 200 and the substrate 100 is saturated, so that the metal mask 200 and the substrate are Assuming that the amount of active etching ions reaching (100) is uniform, when the pitch of the pattern of the metal mask 200 is nanosize, the active etching ion paper is a substrate on which the metal mask 200 is not located ( It can be seen that the probability that the active etching ionic species can enter the region of the substrate 100 where the metal mask 200 is not located decreases as the angle θ ₄ that can enter the 100) region decreases.

The decrease in the probability that the above-described active etching ion paper can enter the portion of the substrate 100 in which the metal mask 200 is not located is decreased, and the aspect ratio (AR) increases as the pitch of the etching mask increases. It is similar to a phenomenon in which the collision with the etching mask 200 increases according to the increased aspect ratio AR due to significant deflection in the lateral direction, thereby decreasing the etching rate of the substrate 100.

Specifically, the decrease in the probability that the active etching ionic species can enter the region of the substrate 100 where the metal mask 200 is not located is a neutral flux that can reach the region of the substrate 100 where the metal mask 200 is not located. This is a phenomenon that occurs when the (Neutral flux) changes.

In addition, the decrease in the probability that the above-described active etching ionic species can enter the portion of the substrate 100 where the metal mask 200 is not located is a sufficient length for the deflected active etching ionic species to enter while the pitch of the pattern of the metal mask 200 is shortened. Because (length) is not secured, it is difficult to exhibit the bowing effect according to the local electric field formed by the metal mask 200.

In contrast, referring to the right drawing of FIG. 10B, the amount of active etching ions constituting the plasma 410 reaching the metal mask 200 and the substrate 100 is saturated, and thus the metal mask 200 and the Assuming that the amount of active etching ions reaching the substrate 100 is uniform, if the pitch of the pattern of the metal mask 200 is microsize, it is activated in the portion of the substrate 100 where the metal mask 200 is not located. The metal mask 200 is formed by an angle of θ _{5 that} is greater than the angle θ _{4 that the} ion species can enter into the portion of the substrate 100 where the metal mask 200 is not located in the left drawing of FIG. 10(b). It can be seen that it can sufficiently enter the portion of the substrate 100 that is not located.

FIG. 10(c) shows the diameter of the nanostructure formed by etching the substrate when the pitch of the metal mask pattern marked in FIG. 10(b) is 3 μm, and FIG. 10(d) shows the case where the pitch of the metal mask pattern is 5 μm. 10(e) shows the diameter of the nanostructure formed by etching the substrate when the pitch of the metal mask pattern is 10 μm, and FIG. 10(f) shows the diameter of the nanostructure formed by etching the substrate when the pitch of the metal mask pattern is 15 μm.

Therefore, referring to FIGS. 10(c) to 10(f), when the array of metal masks has a micro-sized pitch, it can be confirmed that there is no significant change in the size control of the nanostructure by undercutting, and at the same time, it is stable. It can be seen that a nanostructure can be formed.

11 illustrates a change in a lateral etching rate of a substrate according to an etching process time when a process of etching a substrate patterned with a metal mask according to an embodiment of the present invention is performed.

Referring to FIG. 11, when the amount of active etching ions is sufficiently saturated in this experimental condition, the diameter of the structure formed by etching the substrate patterned with the metal mask according to an embodiment of the present invention decreases as the etching time increases. , It can be seen that the depth of the structure formed by etching the substrate patterned with the metal mask linearly increases as the etching time increases.

That is, it can be seen that the lateral etch rate of the substrate patterned with the metal mask according to the embodiment of the present invention decreases as the etching time increases, but the vertical etch rate of the substrate increases as the etching time increases.

Specifically, if the etching time is as short as 128(s), it can be seen that the lateral etching rate of the substrate patterned with the metal mask is high, but in the non-Bosch process without the process of forming a protective film, the longer the etching time, the more the metal mask It can be seen that the side etch rate tends to decrease through sputtering and re-deposition due to the interaction between the and active etching ions. Specifically, the side etch rate decreases and then becomes saturated.

In the above-described sputtering, when ions are accelerated to a high energy of several hundreds of eV or more and collide with a solid material, atoms constituting the material are bounced out.

Therefore, the degree to which the substrate on which the metal mask is patterned according to an embodiment of the present invention is cut in the vertical direction may be determined according to the amount of active etching ions and the exposure time, and the degree of undercutting according to the bowing effect is determined using the etching time. It can be adjusted to prepare a nanostructure.

Therefore, the method of manufacturing a nanostructure according to an embodiment of the present invention actively utilizes side effects that occur in the dry etching process, thereby causing a cost loss due to errors and risks that may occur during the dry etching process. Can be reduced.

In addition, since the nanostructure manufacturing method according to an embodiment of the present invention forms individual structures, characteristics according to individual sizes can be seen, and by borrowing a method that deviates from the lithography/etching process that was performed with the conventional semiconductor process, It has the advantage of being able to create ultra-fine patterns that cannot be made.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the technical field to which the present invention belongs can make various modifications, changes, and substitutions within the scope not departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of the present invention, but are for description, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings. . The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: substrate 200: metal mask

Claims (9)

Patterning a metal mask on the substrate according to a preset pattern; And
Including, among the surfaces of the substrate, dry etching the surface of the substrate exposed to the outside in addition to the surface on which the metal mask is patterned; and
Dry etching the surface of the substrate,
When performing the dry etching, dry etching the surface of the substrate exposed to the outside by using a local electric field in which the intensity of the electric field generated around the metal mask patterned on the substrate is relatively high in some portions of the patterned metal mask But,
The method of manufacturing a nanostructure, characterized in that dry etching the surface of the substrate by controlling the trajectory of active etching ions, which are ions reacted and etched with the substrate using the formed local electric field. delete The method of claim 1,
The dry etching step,
The method of manufacturing a nanostructure, characterized in that by adjusting the thickness of the metal mask to change the local electric field to adjust the angle at which the orbit of the active etching ions is bent. The method of claim 3,
The metal mask
Method for producing a nanostructure, characterized in that it has a thickness in the range of 40nm to 100nmn. The method of claim 1,
The dry etching step,
When the amount of the active etching ions reaching the metal mask and the substrate is saturated, the side of the substrate is etched by changing the deflection of the saturated active etching ions according to the diameter of the metal mask having a preset thickness. The method of manufacturing a nanostructure, characterized in that dry etching the surface of the substrate by controlling the degree of lateral etching indicating the degree to which it is performed. The method of claim 1,
The dry etching step,
The method of manufacturing a nanostructure, characterized in that by adjusting the pitch of the metal mask pattern to control the angle at which the trajectory of the active etching ions is bent. The method of claim 1,
The dry etching step,
As the dry etching time increases, the degree of side etching of the substrate decreases and the degree of vertical etching of the substrate increases, and the degree of side etching of the substrate is adjusted according to the time of the dry etching. A method for manufacturing a nanostructure, characterized in that dry etching the surface. The method of claim 1,
The step of patterning the metal mask,
Applying a photoresist layer on the substrate;
Forming a photoresist pattern by developing a photoresist layer applied on the substrate into the preset pattern; And
Including; depositing the metal mask according to the formed photoresist pattern,
The local electric field is formed near the edge or sidewall of the patterned metal mask,
The dry etching method of manufacturing a nanostructure, characterized in that the reactive ion etching (Reactive Ion Etching, RIE). The nanostructure produced by the method according to any one of claims 1, 3 to 8.

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