KR20170141353A - Three-dimensional nanometer structure fabricating method - Google Patents

Abstract

According to another aspect of the present invention, there is provided a method for fabricating a 3D nanometer structure, including: forming a sacrificial layer on a substrate; forming an upper material on the sacrificial layer; controlling an internal diffusion of the sacrificial layer using an etchant; Forming an encapsulation material on the substrate including a sacrificial layer, and etching the sacrificial layer using an etchant. As a result, it is possible to manufacture a 3D nanometer structure in which a nanometer-sized material requiring crystallization is arranged in a large area, and a nanometer structure can be manufactured quickly and easily using diffusion, And can be reused.

Description

[0001] THREE-DIMENSIONAL NANOMETER STRUCTURE FABRICATING METHOD [0002]

The present invention relates to a 3D nanometer structure manufacturing method, and more particularly, to a fabrication method for fabricating a nanometer-sized structure by adjusting a degree of internal diffusion of a sacrificial layer.

When the material is reduced to the nano level, it exhibits unusual physical and chemical properties. Recently, interest in the field of flexible electronic devices has rapidly increased, and studies for applying nanomaterials have been actively conducted to improve the performance thereof.

For example, nano-wires have traditionally used bottom-up or top-down based manufacturing methods. Bottom-up base is a manufacturing method using chemical synthesis of gas phase and liquid phase, and it is possible to produce high quality nanowires of polycrystalline. However, the material selectivity is relatively narrow, and there is a restriction of size control due to stress and accumulation due to growth. In addition, it is difficult to obtain a high degree of alignment when the prepared nanomaterials are aligned on a substrate.

The top-down base is a manufacturing method using deposition and etching, which can produce various nanomaterials at high speed, but the crystallization is not carried out and the quality is bad, and various applications (for example, piezoelectric) due to crystallization are very limited .

That is, there is no method currently available for forming crystallized nanomaterials while maintaining alignment in a large-area flexible substrate.

In the mechanical, electronic, and material fields, the characteristics of the product are greatly affected by the structure and physical properties of the device. It is easy to change the structure of a device in the macroscopic world, but in the micro-microscope world of micro or nanometer, it is not easy to make the desired structure due to the limitation of the process method.

Recently, optical lithography methods and various micromachining techniques have been developed to produce a desired shape in a two-dimensional shape, but it is still difficult to manufacture a desired microstructure in a three-dimensional shape.

Recently, a method of using a sacrificial layer as a method for manufacturing a three-dimensional structure of a microstructure has been proposed. This is a method of manufacturing a three-dimensional structure by selectively etching a material existing between each layer after manufacturing a multilayer structure of various materials.

FIG. 1 is a prior art using a top-down type and a transfer using a sacrificial layer, and a nanomaterial having a high degree of alignment with a large area can be formed on a flexible substrate. However, there is a problem that the use of substances requiring crystallization is very limited.

For example, as shown in FIG. 1, when annealing is performed prior to transfer, the bonding force between the mother substrate and the nanomaterial becomes strong, which makes transfer difficult (step (a) → (b) → (c) → (A) → (b) → (d) → (f)) when annealing is performed after the transfer, the flexible substrate is damaged or destroyed due to the high temperature. Therefore, it is virtually impossible to manufacture nanostructures in which the crystallized nanomaterials are aligned in a large area by the conventional method as shown in FIG.

In order to maximize the properties of nanomaterials, it is necessary to be able to control the size and control of nanomaterials for practical industrial level applications, to ensure the reliability of large-area manufacturing, and to select large-area materials and substrates for various applications and applications However, it is difficult to guarantee this by the present technology including the above-mentioned method.

On the other hand, the sacrificial layer process has made it possible to fabricate various types of three-dimensional micrometer structures, but has limitations in the nanometer size. The etching process of the sacrificial layer is carried out through the movement and reaction of the substance that plays the role. In the macroscopic world and the micrometer world, the movement of the substance is easily carried out through the convection of the substance, Level material environment, the velocity fields due to external forces are difficult to develop (difficult to generate Poiseuille flow), and only by diffusion based on differences in chemical potential.

Diffusion is difficult to fabricate three-dimensional microstructures because the material movement rate is very slow and the diffusion distance can be saturated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art and the present technical requirements, and an object of the present invention is to provide a 3D nano-scale structure capable of fabricating a three- And to provide a method of manufacturing a meter structure.

It is another object of the present invention to provide a 3D nanometer structure manufacturing method capable of quickly and easily fabricating a nanometer structure using diffusion.

It is another object of the present invention to provide a 3D nanometer structure manufacturing method capable of reusing a mother substrate.

According to another aspect of the present invention, there is provided a 3D nanometer structure fabrication method comprising: forming a sacrificial layer on a substrate; Forming an upper material on the sacrificial layer;

Adjusting an internal diffusivity of the sacrificial layer using an etching solution; Forming an encapsulation material on the substrate including the sacrificial layer whose internal diffusivity is controlled; And etching the sacrificial layer using an etching solution.

And crystallizing the upper material through annealing after forming the upper material.

And the crystallized upper material may be BaTiO ₃ .

In addition, the step of controlling the degree of internal diffusion may partially etch the sacrificial layer by adjusting the etching time of the sacrificial layer.

The step of etching the sacrificial layer may completely etch the remaining portion of the partially etched sacrificial layer.

Also, the substrate may be a grating substrate.

According to another aspect of the present invention, there is provided a method for fabricating a 3D nanometer structure, including: depositing a sacrificial layer on a substrate; Depositing a nanowire material on the sacrificial layer; Damaging the sacrificial layer using an etchant; Laminating a flexible substrate onto a substrate comprising the sacrificial layer; Etching the sacrificial layer using an etching solution; And separating the laminated flexible substrate from the substrate.

The method may further include crystallizing the nanowire material through annealing after depositing the nanowire material.

In addition, the nanowire material crystallized may be BaTiO ₃ .

The step of damaging the sacrificial layer may control the degree of internal diffusion of the sacrificial layer by partially etching the sacrificial layer by controlling an etching time of the sacrificial layer.

In addition, the step of completely etching the sacrificial layer may completely etch the remaining portion of the partially etched sacrificial layer.

The substrate may be a grating substrate.

Further, the method may further include reusing the substrate on which the flexible substrate is separated.

According to the method of manufacturing a 3D nanometer structure according to the present invention having the above-described structure, a 3D nanometer structure in which a nanometer-sized material requiring crystallization is arranged in a large area can be manufactured. In addition, it is possible to quickly and easily fabricate the nanometer structure using diffusion, and it has an economical effect that the mother substrate can be reused.

1 is a schematic diagram showing a transfer method using a conventional top-down method.
FIG. 2 is a schematic diagram illustrating the control of the internal diffusion of the 3D nanometer structure fabrication method according to the present invention.
3 is a schematic diagram illustrating a method for fabricating a 3D nanometer structure according to an embodiment of the present invention.
FIG. 4 is a scanning electron microscope (SEM) image showing a variation of an internal diffusivity of a sacrifice layer according to an etching time in a 3D nanometer structure fabrication method according to an embodiment of the present invention.
FIG. 5 is a graph showing changes in the degree of internal diffusion of a sacrificial layer according to an etching time in a 3D nanometer structure fabrication method according to an embodiment of the present invention.
6 is an application example of a 3D nanometer structure manufacturing method according to the present invention.
7 is a scanning electron micrograph showing a cross-section of a semiconductor device and a nanowire channel formed by the method shown in FIG.
8 is a view illustrating a 3D nanometer structure manufacturing method according to another embodiment of the present invention.
9 is a graph showing the degree of crystallization of the upper material by the 3D nanometer structure manufacturing method according to the present invention.
10 is a photograph showing the result of the transfer by the 3D nanometer structure manufacturing method according to the present invention.
FIGS. 11 and 12 are graphs showing the characteristics of the device manufactured by the material transfer by the 3D nanometer structure manufacturing method according to the present invention, and the results thereof.

The following description of the invention refers to the accompanying drawings which illustrate, by way of example, specific embodiments that may be practiced. The described embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment.

It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

A method of fabricating a 3D nanometer structure according to an embodiment of the present invention includes forming a sacrificial layer on a substrate, forming an upper material on the sacrificial layer, adjusting an internal diffusion of the sacrificial layer using an etchant, Forming an encapsulation material on the substrate comprising the controlled sacrificial layer, and etching the sacrificial layer using the etchant.

The step of adjusting the degree of internal diffusion in each step will be described first.

FIG. 2 is a schematic diagram illustrating the control of the internal diffusion of the 3D nanometer structure fabrication method according to the present invention. The 3D nanometer structure manufacturing method according to the present invention proposes a method of improving the internal diffusivity by controlling the porosity of the sacrificial layer.

First, a sacrificial layer 110 is formed on the substrate 100, and an upper material 120 is formed on the sacrificial layer 110. At this time, as shown in FIG. 2A, very small pin holes having a size of nanometer or less are formed in the upper material 120. The pinholes formed in the top material 120 provide a passage through which the etchant flows into the sacrificial layer 110 located below the top material 120. However, since the size of the passage is very small, the etchant gradually reaches the sacrificial layer 110 with time.

The sacrificial layer in contact with the etching solution is partially etched as shown in FIG. 2 (b). Though the upper material 120 is not removed through the control of the etching time, the sacrificial layer 110 is damaged by etching, which makes the sacrificial layer 110 porous. When the structure of the sacrificial layer 110 becomes porous, the degree of diffusion is increased by a millington quirk model.

The 3D nanometer structure manufacturing method according to the present invention can easily fabricate a 3D nanometer by making the sacrificial layer 110 porous structure to increase the degree of diffusion.

3 is a schematic diagram illustrating a method for fabricating a 3D nanometer structure according to an embodiment of the present invention.

3 (a), a sacrificial layer 110 is formed on a substrate 100, and an upper material 120 is formed on a sacrificial layer 110. Here, the substrate 100 may be a three-dimensional nanograting substrate made of silicon (Si). The sacrificial layer 110 may be, for example, a material such as chromium (Cr) and may be formed on the substrate 100 by deposition. The top material 120 may be, for example, a material such as gold (Au) and may be formed on the substrate 100 by vapor deposition. However, the types and formation methods of the substrate 100, the sacrificial layer 110, and the upper material 120 are not limited to the examples described above.

Thereafter, an internal diffusion degree adjustment step of the sacrifice layer described with reference to FIG. 2 is performed. In other words, the substrate 100 on which the sacrificial layer 110 and the upper material 120 are formed is immersed in an etchant to form the sacrificial layer 110 into a porous structure (Fig. 3 (c)).

At this time, the internal diffusivity can be determined according to the etch time by the etchant, and will be described in more detail below with reference to FIGS. 4 and 5. FIG.

Thereafter, an encapsulation material (e.g., PUA) 160 is formed on the substrate 100 including the sacrificial layer 110 whose internal diffusion is controlled (FIG. 3 (d)). At this time, it is preferable that the encapsulation material 160 is a material that can permeate etchant.

The substrate 100 encapsulated by the encapsulation material 160 is immersed again in the etching solution to selectively etch the sacrificial layer 110 (FIG. 3 (e)). At this time, since the sacrificial layer 110 is etched by the etching performed in the internal diffusion degree controlling step, the remaining sacrificial layer is etched in this step (FIG. 3 (f)).

On the other hand, after the remaining sacrificial layer is etched, it may further include a plasma processing step for surface smoothing (not shown).

FIG. 4 is a scanning electron microscope (SEM) image showing changes in the degree of internal diffusion of the sacrificial layer 110 according to the etching time, and FIG. 5 is a graph showing changes in the degree of internal diffusion of the sacrificial layer 110 according to the etching time. Here, an experiment was conducted in which the substrate 100, the sacrificial layer 110, the upper material 120, and the encapsulation material 160 were composed of Si, Cr, Au, and PUA, respectively.

4 (a), 4 (b), and 4 (d) show an etch time of 0 seconds, an etch time of 60 seconds, an etch time of 120 seconds, The etching time was set to 180 seconds. Also, in the step of finally etching the remaining sacrifice layer, the etch time was all 4 hours.

Referring to FIGS. 4 (a) to 4 (d), it can be seen that the degree of diffusion of the etching solution into the sacrificial layer 110 in the etching step related to the control of the internal diffusion degree is changed. The diffusion coefficient is extracted from the degree of etching, and the change and pattern of the diffusivity are compared with the theory of diffusion degree by porosity. In the graph of FIG. 5, the axis of abscissas indicates the diffusion control time, and its unit is sec. And, the vertical axis means the extracted diffusion coefficient, and its unit is m ² / s, which means the diffusion area per hour.

The graph of FIG. 5 shows that the experimental and theoretical variations are very similar, which means that the porosity inside the sacrificial layer is changed by the method of fabricating the 3D nanometer structure according to the present invention, and the degree of diffusion is controlled thereby.

Meanwhile, in the 3D nanometer structure manufacturing method according to the present invention, after forming the upper material 120, crystallizing the upper material may be further included.

As described in connection with FIG. 1, there is a limit to the manufacture of 3D nanometer structures in the case of materials requiring crystallization. This means that an annealing step for crystallization can not be included.

Unlike the prior art, the 3D nanometer structure manufacturing method according to the present invention enables crystallization of the upper material 120 through annealing. In other words, crystallization is performed through annealing after formation (deposition) of the upper material 120, and damage is not caused even through the etching process sequentially.

In particular, in the case of a BaTiO ₃ material whose piezoelectric characteristics are typically improved through crystallization, it is very difficult to fabricate a 3D nanometer structure because it can not be subjected to an annealing step in the prior art. However, according to the method of manufacturing a 3D nanometer structure according to the present invention Even when BaTiO ₃ is used as the upper material 120, it is possible to improve the piezoelectric characteristics through annealing and also to fabricate a 3D nanometer structure.

FIG. 6 is an application example of the 3D nanometer structure fabrication method according to the present invention, and sequentially shows steps of forming a semiconductor device including a nanowire channel.

First, a substrate 100 of a grating structure is provided, and a sacrificial layer 110 and an upper material 120 are sequentially formed in a certain region on the substrate 100 (FIGS. 6 (a) to 6 (c)).

6 (d), the sacrificial layer 110 is formed into a porous structure using an etchant to control the degree of internal diffusion and form an inlet and an outlet, ).

Finally, the remaining portion of the sacrificial layer 110 is etched using an etchant to form the nano channel 140 (Fig. 6 (f)).

On the other hand, it may further include a plasma processing step for smoothing the surface of the substrate 100.

FIG. 7 is a scanning electron microscope photograph showing the entirety of a semiconductor device formed by the method shown in FIG. 6 and a cross section of a nanowire channel 140, The sacrificial layer) can be easily removed and the nanowire channel can be easily formed.

8 is a view illustrating a 3D nanometer structure manufacturing method according to another embodiment of the present invention.

First, a nano-grating substrate 100 is provided (Fig. 8 (a)). A sacrificial layer 110 and an upper material 120 are deposited on the substrate 100 (Fig. 8 (b) (c)). At this time, the upper material 120 may be a material for forming nanowires. Thus, the top material 120 can be a nanowire material, for example, BaTiO ₃ , which improves piezoelectric properties when crystallization is performed.

The sacrificial layer 110 and the upper material 120 are annealed on the deposited substrate 100 (Fig. 8 (d)). This may be referred to as an annealing step or a crystallization step.

When the crystallization of the upper material 120 is performed, a step of damaging the sacrificial layer 110 is performed (Fig. 8 (e)). The damage step of the sacrificial layer 110 corresponds to the step of adjusting the degree of internal diffusion described above. In other words, the etchant contacts the sacrificial layer 110 through the upper material 120 to etch a portion of the sacrificial layer 110 (Fig. 8 (e) (f)).

A flexible substrate 150 is laminated on the substrate including the damaged sacrificial layer 110 (FIG. 8 (g)). After the flexible substrate 150 is laminated, the remaining portion of the sacrificial layer 110 is completely etched by immersing the flexible substrate 150 in an etchant (Fig. 8 (g)).

Finally, the flexible substrate 150 is peel-off from the substrate 100. 8 (h), the sacrificial layer 110 is completely etched so that the upper material 120 can be easily separated from the substrate 100 (FIG. 8 (j)).

Meanwhile, the separated flexible substrate 150 may further include a plasma processing step for surface smoothing.

9 is a graph showing the degree of crystallization of the upper material by the 3D nanometer structure manufacturing method according to the present invention. The lower graph is the degree of crystallization of the upper material 120 immediately after deposition in the step of FIG. 8 (c), and the intermediate graph shows the degree of crystallization immediately after the annealing at 700 ° C. in the step of FIG. 8 (d) 8 shows the degree of crystallization immediately after the sacrifice layer 110 is damaged in step (e). 9, after the crystallization of the upper material 120 in the annealing step (FIG. 8 (d)), the upper material 120 is etched for the sacrificial layer damage step (FIG. 8 (e) It can be seen that the crystallization is not damaged.

That is, according to the method of fabricating the 3D nanometer structure according to the present invention, the problem of the conventional technique described with reference to FIG. 1 is solved, and the 3d nanometer structure can be manufactured using the upper material that needs crystallization.

Meanwhile, since the substrate 100 from which the flexible substrate 150 is removed in the step of FIG. 8 (i) can be reused and provided again to the substrate 100 of FIG. 8 (a) Effect can be achieved.

10 is a photograph showing the results of the transfer to the 3D nanometer structure manufacturing method of the various embodiments described above. The result is a 200-line and space nano-grating substrate.

Fig. 10 (a) shows an optical photograph with a scale bar of 2 cm, and Figs. 10 (b) to 10 (e) show scanning electron microscopic photographs of respective parts shown in Fig. 10 (a). 10 (a) to 10 (e), it can be seen that the nanomaterial (wire form) is uniformly transferred to an area of about 2 × 2.5 cm. From FIG. 10 (f) You can see that it is perfectly aligned.

10 (g) is a photograph showing the cross-sectional EDS material analysis (scale bar: 100 nm) of the transferred nanowire. The main components of the nanowire produced are barium Ba (indicated by blue dots), titanium Ti) (indicated by red dots) and oxide (O) (indicated by green dots). From the mapping data shown in FIG. 10 (g), the mass percentages of the main components of the transferred nanowires were 52.77 mass%, 24.47 mass%, and 11.58 mass%, respectively, and chromium (Cr) was detected as 1.18 mass%. This result means that the chromium in contact with BaTiO ₃ produces an alloy, but the alloy material is substantially etched in step (h) of FIG.

FIGS. 11 and 12 are graphs showing the characteristics of the device manufactured by the material transfer by the 3D nanometer structure manufacturing method according to the present invention, and the results thereof.

First, BaTiO ₃ whose piezoelectric characteristics are improved by crystallization is used as the upper material 120. In FIG. 11 (a), silver electrodes are formed at both ends of the transfer material, and attached to a finger , And the characteristics were evaluated while bending and spreading the fingers as shown in Fig. 11 (b).

12 (a) and 12 (b) show piezoelectric results (current and voltage) when crystallization is performed by performing heat treatment, and FIGS. 12 (c) and 12 (Current and voltage).

As shown in the graphs of FIGS. 12 (a) and 12 (b), when the heat treatment was performed, improved material properties were obtained. This is because the piezoelectric property of BaTiO ₃ used as the upper material 120 is improved by crystallization. This makes it possible to apply sensors and energy harvesting devices.

On the other hand, as shown in the graphs (c) and (d) of FIG. 12, if the heat treatment is not performed, the piezoelectric characteristics are not improved.

Therefore, the 3D nanometer structure manufacturing method according to the present invention can be applied to a material such as silicon because it can affect the crystallization characteristics of a material, and because it can be applied to a flexible semiconductor device, the demand will be very high.

The above-described method for fabricating a 3D nanometer structure relates to a novel transfer method for solving the crystallization problem that was not possible in the conventional formation and transfer of nanomaterials on a flexible substrate, and can be applied to a flexible electronic device using various materials. In addition, it is suitable for mass production using a simple process, and can be used for various applications (for example, an energy harvesting device using a piezoelectric material, etc.) due to its ability to control the crystallization of a material, This is possible. Furthermore, by transferring a pattern uniformly aligned to a large area, it is possible to design the device using the degree of alignment and to efficiently use the material (easy to improve the characteristics).

The features, structures, effects, and the like described in connection with the above embodiments are included in one embodiment of the present invention, and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100 ‥‥‥‥‥‥‥‥‥‥‥‥ Substrate
110 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Sacrificial layer
120 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
130 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
140 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Nanowire channel
150 ... ... ... ... ... ... ... Flexible substrate

Claims (13)

Forming a sacrificial layer on the substrate;
Forming an upper material on the sacrificial layer;
Adjusting an internal diffusivity of the sacrificial layer using an etching solution;
Forming an encapsulation material on the substrate including the sacrificial layer whose internal diffusivity is controlled; And
And etching the sacrificial layer using an etchant. The method according to claim 1,
And crystallizing the top material through annealing after forming the top material. ≪ Desc / Clms Page number 21 > 3. The method of claim 2,
Wherein the crystallized upper material is BaTIO ₃ . The method according to claim 1,
Wherein adjusting the internal diffusivity comprises partially etching the sacrificial layer by controlling an etch time of the sacrificial layer. 5. The method of claim 4,
Wherein etching the sacrificial layer comprises etching the remaining portion of the partially etched sacrificial layer. The method according to claim 1,
Wherein the substrate is a grating substrate. Depositing a sacrificial layer over the substrate;
Depositing a nanowire material on the sacrificial layer;
Damaging the sacrificial layer using an etchant;
Laminating a flexible substrate onto a substrate comprising the sacrificial layer;
Etching the sacrificial layer using an etching solution; And
And separating the laminated flexible substrate from the substrate. 8. The method of claim 7,
And crystallizing the nanowire material through annealing after depositing the nanowire material. ≪ Desc / Clms Page number 13 > 9. The method of claim 8,
Wherein the crystallized nanowire material is BaTIO ₃ . 8. The method of claim 7,
The step of damaging the sacrificial layer adjusts an internal diffusion of the sacrificial layer by partially etching the sacrificial layer by controlling the etching time of the sacrificial layer. 11. The method of claim 10,
Wherein etching the sacrificial layer comprises etching the remaining portion of the partially etched sacrificial layer. 8. The method of claim 7,
Wherein the substrate is a grating substrate. 8. The method of claim 7,
And reusing the substrate having the flexible substrate separated therefrom.

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